Thursday

September 29, 2016
Total # Posts: 44,236

**ALGEBRA**

If there are x ml of 20% then the rest (100-x) is 40%. So, add up the acid in the parts; it must equal the acid in the result: .20x + .40(100-x) = .24*100 and that's liters, not leters. When you get your answer, note that 24% is 1/5 of the way from 20 to 40, so 1/5 of the ...

*September 11, 2016*

**Math**

y-x = 20 (x+y)/3 = 40

*September 11, 2016*

**college**

60 rev/min * 2π rad/rev = 120π rad/min the linear speed is just radius * angular speed 120π/min * 15in * 1ft/12in * 1min/60s = (120π*15)/(12*60) ft/s

*September 11, 2016*

**math**

First step: distributive 6x-8 = 8x-11 now what?

*September 11, 2016*

**Math**

Tn must surely be (n+1)x + (-1 + 2(n-1)) = (n+1)x + 2n-3

*September 11, 2016*

**math**

note that S increases by 5 for every +1 change in N.

*September 11, 2016*

**Math**

exactly reversed. How can you possibly add two positive numbers and sometimes get a negative result???

*September 11, 2016*

**Algebra**

y = mx+b 21m+b = 58 43m+b = 42.6 Solve for m and b, and then figure y when x=59. Or, note that 22 minutes of driving covered 15.4 miles. So, after 16 more minutes, he covers (16/22)(15.4) more miles. Subtract that from 42.6

*September 11, 2016*

**Algebra 1 Foundation Concepts rewrite**

6 B,C http://www.virtualnerd.com/algebra-2/equations-inequalities/real-numbers/number-types/natural-and-whole-numbers-definition Surely your text explains all this.

*September 11, 2016*

**Math**

(a) 10(+0.30) = +3.00 That's my work so far. Have any of your own?

*September 11, 2016*

**Math Trigonometry**

use the law of cosines. The included angle is 50°

*September 11, 2016*

**Mathematics**

(b) clearly d=4, since T16-T8 = 8d = 32 Now do (a) and (c) For (c), note that T20-T16 = 4d

*September 11, 2016*

**Math Trigonometry**

actually, if you draw the parallelogram, you will see that you have the wrong diagonal. R^2=22^2+35^2-2*22*35*cos(180-52) If the vectors are u and v, you want |u+v|, not |u-v|

*September 11, 2016*

**Trig**

use the law of cosines. The included angle is 50°

*September 11, 2016*

**Math**

you have a problem balancing your grouping symbols. How did you get 14?

*September 11, 2016*

**Math**

-2+3[6-(1-9)] -2+3[6-(-8)] -2+3[6+8] -2+3[14] -2+42 40

*September 11, 2016*

**Math Domains**

You know that you cannot take the square root of a negative number. That means that you must have x(x-2) >= 0 So, either both factors are negative, or both are positive. Thus, the domain is (-∞0]U[2,∞) You can visualize this by graphing the parabola. It opens ...

*September 11, 2016*

**Math**

Your math is correct, but your choice is not Think of (1/2) as a unit, like books, dollars, etc 9 of them divided by one of them is 9 9/2 km is the goal 1/2 is each trip So, 9 is the number of trips needed to reach the goal: (D)

*September 11, 2016*

**Math**

note that (p-q)^2 = p^2 - 2pq + q^2

*September 11, 2016*

**algebra**

what, reposting after only 3 minutes? impatient much?

*September 11, 2016*

**math**

a little synthetic division shows 4x^2-10x+21 R -41

*September 11, 2016*

**math**

(3rd)^2 = 9 rd^2

*September 11, 2016*

**College Algebra**

by steadily, do you mean it rises by the same amount each year or it rises by the same percent each year ?

*September 11, 2016*

**Algebra**

well, it appears to drop 400 each time. So, what does that tell you?

*September 11, 2016*

**Math**

divide by 2 and you have 3/2 cm : 1m

*September 11, 2016*

**math**

or x40

*September 11, 2016*

**maths**

There sure is a lot of gobbledegook there. If we say that the center lies on the line x = 2t-1 y = 3t+1 Apparently the center of the circle lies on the line y = (3x+5)/2 The circle passes through (-3,-1) So, we need (-3-h)^2 + (-1-(3h+5)/2)^2 = 100 h=3 or -105/13 so, k= 7 or -...

*September 11, 2016*

**Calculus**

I assume you meant to ask: How fast is the shadow moving on the wall, when the distance from the man to the center of the courtyard is 1/2 r Let's set this up in polar coordinates. Let's call the radius a, so we can use r as a function of θ. Set the light at the ...

*September 11, 2016*

**Math**

64.4/20 * 100 cm

*September 11, 2016*

**Algebra**

1/30 + 1/25 = (5/6)/x

*September 11, 2016*

**Math**

sin(kx) has period 2π/k the other requires some numeric or graphical techniques: But you know it will be somewhere near x=25, since |sinx| <= 1 and 25-x=0 at x=25 http://www.wolframalpha.com/input/?i=25+%E2%88%92+x+%E2%88%92+sin(x)

*September 11, 2016*

**Math**

1. What is one period of the function f(x) = 120 sin(120πx). 2. When does f(x) = 25 − x − sin(x) cross the x-axis?

*September 11, 2016*

**Algebra**

Ah, I think you mean f(x) = a * b^x I guess that means a/b^3 = 30 ab^1 = 13 Is that anywhere near what is wanted? If not, can you explain a bit, or give a pointer to examples of this notation?

*September 11, 2016*

**algebra**

If it is a multiple of 9, its digits must add to a multiple of 9. I think you are missing a dash, since it cannot start with 6 and end with 5 and be a palindrome.

*September 11, 2016*

**Exponential Inequalities**

2/5^(5x-1) >= 25/4 8 >= 5^2*5^(5x-1) 8 >= 5^(5x+1) 5x+1 <= log8/log5 x <= (log8/log5 - 1)/5

*September 11, 2016*

**Math**

S: 3n+1 L: 2n

*September 11, 2016*

**maths**

the area consists of six isosceles triangles, each with base = 3.5m Check how to find the apothem of a regular hexagon. If the apothem is a, then the height of each triangle is the slant height of the pyramid: √(1.9^2 + a^2)

*September 11, 2016*

**maths - clarify**

is that √(2 cotx) or (√2)cotx?

*September 11, 2016*

**Mathematics**

12800((1+.15/4)^2 - 1)

*September 11, 2016*

**math**

1+3(n-1) = 3n-2

*September 11, 2016*

**differential equation**

see related questions below

*September 11, 2016*

**Geometry**

consider that the diagonal of the square is the diameter of the circle.

*September 11, 2016*

**Geometry**

see related questions below

*September 11, 2016*

**math**

a quadrant is 1/4 of a circle. I'm sure you can find the area of a whole circle, yes?

*September 10, 2016*

**Math trigo**

is that 660 minutes? If so, 660' = 11° If you meant 660°, then since 660 = 360+300, tan660° = tan300° Now, since 300 = 360-60, tan660° = -tan60°

*September 10, 2016*

**Math**

left 4, up 6

*September 10, 2016*

**Geometry**

since MP bisects <LMN, m<LMP is 1/2 of m<LMN. So, m<LMN = 2(m<LMP) 10x-6 = 2(4x+3) Now find x and m<LMN = 10x-6

*September 10, 2016*

**Math**

it's easy to fin P1(no cubes) or P2(no spheres). P(some of each) = 1 - (P1+P2)

*September 10, 2016*

**Math**

while the tangent line is the limit of the secants lines, that was not the question. It said h > 0. Draw a parabola. The secants are always steeper than the tangents. So, (A)

*September 10, 2016*

**Calculus 1**

h = d/4 = r/2 So, r = 2h v = π/3 r^2h = 4π/3 h^3 dv/dt = 4πh^2 dh/dt Now just plug in your numbers.

*September 10, 2016*

**Physics**

yes, the final velocity is ∆x/∆t = 630km/12.6hr = 50 km/hr So, the acceleration is ∆v/∆t: (50km/hr)/(1/2 hr) = 100km/hr^2 You might want to put that into standard SI units of m/s^2.

*September 10, 2016*

**Pre-Calculus**

5 minutes is 1/12 of an hour. The hand makes one complete circle in an hour So, it moves 1/12 of the whole circumference in 5 minutes. I assume you know how to find the circumference of a circle of radius 3. Note that since there are 2π radians in a whole circle, that is ...

*September 10, 2016*

**8th Grade Pre-Algebra**

starting at the decimal point (or the rightmost digit if there is none), count how many places left you have to move the point till the number is between 1 and 10 (less than 10). Note that 10^0 = 1 108,000,000 = 108,000,000 x 10^0 108,000 x 10^3 108 x 10^6 10.8 x 10^7 1.08 x ...

*September 10, 2016*

**Algebra**

rate of change is how fast y changes when x changes by 1. y = -2x+6 Note that -2 in front of x. That is the slope of the line, or also the rate of change. You can see that adding 1 to x add -2 to y. So, -2 is the rate of change (of y with respect to x). y = -3x+10 slope = -3 ...

*September 10, 2016*

**Alg**

see prior post

*September 10, 2016*

**Algebra**

I see you have interpreted it as 5-2[5(-2)+4(2)]/[-3(3)+3(-4)] -9-12 = -21, not -24 = 5 - 2(-2/-21) = 5 - 4/21 = 101/21 I fail to see how you could do all the hard stuff you did, and then say you cannot even figure 5-2 even...

*September 10, 2016*

**Algebra**

5-2[5(-2)+4(2)/-3(3)+3(-4)] 5-2[-10+8/-3(3)+3(-4)] 5-2[-10-8-12] 5-2[-30] 5+60 65

*September 10, 2016*

**Alg**

25x = 75 We're happy to help find solutions, but don't make us ask the questions as well, ok?

*September 10, 2016*

**MAth**

1+4*3+3(3^2-2^2)=28

*September 10, 2016*

**evans**

well, P(success) = 1/13 so use that as usual

*September 10, 2016*

**Math**

distributive

*September 10, 2016*

**general adult education**

same stupid riddle.

*September 10, 2016*

**Math**

5.8/x = cos60°

*September 10, 2016*

**Algebra**

3+4=7 minutes before the chopper lands.

*September 10, 2016*

**Math**

yes. That means that 168.720 / 0.024 * 1000/1000 = 168720/24

*September 10, 2016*

**math (opt) math 2**

If the sides are 30 and 40, the diagonal is 50 so, if the height is h, h/50 = tan30°

*September 10, 2016*

**math or chemistry**

That is correct. But really, if you add -2 + -3 + -3 you get -8

*September 10, 2016*

**Math**

well, 24 = 12*2 ...

*September 10, 2016*

**Accounting**

might neighborly of them, I must say.

*September 10, 2016*

**Algebra**

a) correct b) x/3 + 15 c) x+15 d) x/3 + 15 = 3/4 (x+15) x = 9 e) Jane = x+15 = 24 Check: Karen is 3/4 * 24 = 18 15 years ago, she was 3, or 1/3 of 9

*September 10, 2016*

**Maths**

recall that dy/dt = dy/dx * dx/dt You have dx/dt = 0.3 so, plug in x=0 dy/dt = (2 - 8/√4) * 0.3 = -0.6

*September 10, 2016*

**Maths**

what are the factors of 108? 1 108 2 54 3 36 4 27 6 18 9 12 So, how can those be used to add up to 30? (Remember that one has to be used twice)

*September 10, 2016*

**Intro to Algebra**

750,000 - 60,000 = 690,000 2017-1977 = 30 years 690,000/30 = 23,000 V(t) = initial amount + amount increased each year •t Answer: V (t)=60,000+23,000t

*September 10, 2016*

**Science**

ok now what?

*September 10, 2016*

**Math 201**

surely you can see that each ticket costs $5

*September 10, 2016*

**math or chemistry**

Hmmm. I get 106.65 x 10^-8 But, you want that in scientific notation, so it is written as 1.0665 x 10^-6 And, considering the number of significant figures, it would probably be better as 1.1 x 10^-6

*September 10, 2016*

**Math 201H**

it looks like each payment was 400 that should help. The balance starts at 14000 and goes down

*September 10, 2016*

**chemnad school computer application**

sum=0 for n=101 to 199 step 2 { sum += n } or, by hand, pair them up: 101 + 199 = 300 103 + 197 = 300 ... how many such pairs are there? Or, since the sum of the 1st n odd numbers is n^2, 100^2 - 50^2 = 7500

*September 10, 2016*

**Math**

j = 3g j = 4b g = 8 Now just find b: j = 3*8 = 24 24 = 4b b = 6

*September 9, 2016*

**physics**

75 mi/hr * 1609m/mi * 1hr/3600s * 3s = (75*1609*3)/3600 m

*September 9, 2016*

**Math**

140 = 2^2 * 5 * 7 168 = 2^3 * 3 * 7 210 = 2 * 3 * 5 * 7 So, what is the biggest number that divides all of those?

*September 9, 2016*

**Physics**

distance: s = 1/2 at^2 speed: v = at

*September 9, 2016*

**Physics**

time rising: 4.9t^2 = 1.29 double that for total hang time. v = 9.8t

*September 9, 2016*

**Math**

can't see the diagram, but just add up the distances. How hard is that?

*September 9, 2016*

**Physics**

4.9t^2 = 370 v = 9.8t

*September 9, 2016*

**math**

well, there are 4 sides, so ...

*September 9, 2016*

**Math**

since the other wall is also 20 ft, and area = length * width, it is 20ft * 20ft = 400 ft^2

*September 9, 2016*

**Algebra**

2^-1 + 4^-5 = 1/2^1 + 1/4^5 = 1/2 + 1/1024 = 513/1024 You can always type in your expressions at wolframalpha.com to verify your answers

*September 9, 2016*

**Math**

read the question again carefully. Only boys or girls in each row. Why did you combine them into rows of 18?

*September 9, 2016*

**Math**

consider that 9 divides both 72 and 90

*September 9, 2016*

**Physics**

F = ma, so together, (6.0+4.0) = 3.2a opposite, (6.0-4.0) = 3.2a

*September 9, 2016*

**Physics**

F = ma, so 0.40a = 25

*September 9, 2016*

**Grammar world**

subject, verb, dir obj, obj complement they | crowned | him / king

*September 9, 2016*

**Algebra**

Hmm. Watch those minus signs. (x^-2)^3 (x^2)^4 = x^-6 * x^8 = x^2 x^2/x^15 = 1/x^13 = x^-13

*September 9, 2016*

**Math**

15 m/s * 1km/1000m * 3600s/hr = 15*3600/1000 km/hr 750m * 1s/15m = 750/15 s

*September 9, 2016*

**math**

The difference in meaning is that -3 is a signed value. It lies to the left of zero +3 is also a signed value, and since it is positive, it lies to the right of zero |-3| is just the physical distance (left or right) of -3 from zero. Since we live in a physical world, all ...

*September 9, 2016*

**Math Help needed quickly**

Think on it. If there were 55 ml alcohol, there would be 45 ml water. That's 10 ml less. We have 20 ml less, so there must be 110 ml alcohol 90 ml water

*September 9, 2016*

**Math - hmmm**

I'm not familiar with this notation. Have you some other information, maybe a subject topic in your text?

*September 9, 2016*

**Math**

just add up the amount of work done by A and B in a minute. Together, they do 1/20 of the job: 1/36 + 1/x = 1/20

*September 9, 2016*