Posts by STEVE

Total # Posts: 54,314

Mathematics

Mathematics
Nope. You want A reread the question carefully It might be better to use >= instead of >_ x < -3 or x >= 5

Math
(-2/5)*(-1 1/4) = (-2/5)*(-5/4) = 10/20 = 1/2

Algebra
yep

Math
work just like any equation... For example, assuming the usual carelessness with parentheses, but watch when multiplying/dividing by negative values. -2/(5x-9) < 9/10 If (5x-9) > 0 (that is, x > 9/5), we have -2 < 9/10 (5x-9) -20 < 9(5x-9) -20 < 45x - 81 61 &...

Math - eh?
huh?

Math
they wanted car:train You gave train:car the numbers are correct, but the ratios are not the same.

Math
There are 2 numbers greater than 4 So, of the choices given, which has exactly 2 possibilities? Hint. It's not A. There are 4 numbers greater than 2.

Math
um ... \$360 (assuming "normally" means "regular")

math
well, how many days in 15 weeks? 93 each day ...

Physics
how long does it take to hit the ground? 20 + 27 sin50° t - 4.9t^2 = 0 Now use that t to find the speeds: vertical speed 27 sin50° - 9.8t horizontal speed: 27 cos50° and the hor distance is just hor speed * time

Physics
see this very closely related question: https://www.jiskha.com/display.cgi?id=1508128463

Pre calc
sorry - the focus cannot be on the directrix maybe you should fix that. However, the parabola (x-h)^2 = 4p(y-k) has a latus rectum of length 4p.

Pre calc
recall that the ellipse x^2/a^2 + y^2/b^2 has major axis 2a minor axis 2b

Pre calc
the complex roots come in pairs, so f(x) = (x-1)(x-3i)(x+3i)(x-(4-i))(x-(4+i))

calculus
draw a diagram. You can see that when the depth is d, the width of the cross-section is also d. So, the area of the cross-section is 1/2 d^2. v = 1/2 d^2 * 800 cm^3

Algebra: simplifying polynomials
clearly this is an exercise in factoring polynomials, so you can cancel common factors. x^3 + x^2 - y^3 - y^2 = (x^3-y^3) + (x^2-y^2) = (x-y)(x^2+xy+y^2) + (x-y)(x+y) x^2-2xy+y^2 = (x-y)^2 u^6 + v^6 + 2u^3 • v^3 = (u^3+v^3)^2 = (u+v)^2 (u^2-uv+v^2)^2 u^3 - v^3 + (u^2 &#...

Physics
I predict that the faster runner will win ...

Algebra HELP
(ax+by)(cx+dy) = (ac)x^2 + (ad+bc)xy + (bd)y^2 (a?x + b?y)(c?x + d?y) = (ac)x + (ad+bc)?(xy) + (bd)y for example (2x-3y)(3x+y) = 6x^2+7xy-3y^2 (2?7 + 3?5)(?7 - 2?5) = 2*7 + (3-4)?(7*5) - 6*5 = 14 - ?35 - 30 = -16 - ?35

Math
well, what are the first 4 primes? hint: 1 is not a prime.

Math
she has enough beads for red: 7/1 = 7 patterns purple: 27/3 = 9 patterns yellow: 24/2 = 12 patterns so, what do you think?

algebra
B: -4x^2 terms are separated by +/- signs.

Calculus II
dQ/dt = k(85-Q) dQ/(85-Q) = k dt ln(85-Q) = kt + c 85-Q = c*e^(kt) Q = 85-c*e^(kt) Q(10) = 50, so 85-c*e^(10k) = 50 c*e^(10k) = 35 c = 35e^(-10k) Q(t) = 85-35e^(-10k)*e^(kt) = 85-35e^(kt-10k) Now, using Q(0) = 0, 85-35e^(-10k) = 0 e^(-10k) = 17/7 -10k = ln(17/7) k = -0.0887 Q(...

Algebra
If there were x students, we are told that .14x = 7 x = 50 check: 14% of 50 = 7 so, 43 students tried out this year, a 14% decrease from the 50 last year.

algebra 2
if you mean p = 1/(rs) + d then p-d = 1/(rs) rs = 1/(p-d) r = s/(p-d) Or, if you mean p = 1/(rs+d) then rs+d = 1/p rs = 1/p - d = (d-p)/p r = (d-p)/(sp)

Math
nope. change the y's to negative. The - sign multiplies the y-value, not the x value. To flip the x's, you'd need something like y = 3?(-x+9)-3

BC Calculus
at a radius r, the volume flowing through per second is dv = 2?rh dr where h is the height of the cylinder. That height is the rate of flow per second, so dv = 2?r(9-r^2) dr dv/dr = 2?r(9-r^2) Now add up for all the thin cylinders of thickness dr, and v = ?[0,3] 2?r(9-r^2) dr...

Maths
the sides of a square are equal, so 2(x+3 + x-2) = 30

Math
There is no way that 106 can be divided into the ratio of 3:2. However, 40 can be so divided, since 40 = 8*5, so 24:16 = 3:2 I suspect a typo.

Math
note that A and B are on the same horizontal line. So, D must also be in line vertically with A and horizontally with C, at (2,4)

Algebra Help!!
It's not, unless you count different roots as being like different variables.

Math
center is (-4,2) c = 2 a = 3 so, b^2 = 5 and the major axis is vertical. That help?

Math
b = 5/2 a = 1 (x+1)^2/1 + (y+2)^2/(25/4) = 1 or (x+1)^2 + 4(y+2)^2/25 = 1 http://www.wolframalpha.com/input/?i=ellipse+(x%2B1)%5E2%2F1+%2B+(y%2B2)%5E2%2F(25%2F4)+%3D+1

Math
from the foci, it is clear that the center is at (6,1) and c = 2 Since the major axis has length 10, a=5 b^2 = 25-4 = 21 so, the equation is (x-6)^2/25 + (y-1)^2/21 = 1 see the data at http://www.wolframalpha.com/input/?i=ellipse+(x-6)%5E2%2F25+%2B+(y-1)%5E2%2F21+%3D+1

Math
What about February? 365/12 = ?

math
y-6 = -1/2 (x-3) Clearly (0,15/2) fits the equation 15/2 is just a number, like any other. What bothers you about it?

Math/Algebra
14*x + 14*2x + 61*365*3x - 14*3x = 6679.80 The original fine was \$0.10/day If leap years were not considered...

Math
everyone knows that for large values of 2, 2+2=5, for small values of 5.

Locus
The line 5 units away from the given line will cross the y-axis somewhere. Pick a point (0,y) Its distance from the line is |6y-1|/10 = 5 6y-1=50 ==> y = 17/2 6y-1=-50 ==> y = -49/6 Now you know that the desired line contains either (0,17/2) or (0,-49/6) Its slope is -4/...

Algebra
1/6 - 1/18 = 1/x x = 9

College Algebra
since time = distance/speed, If B has speed x, then 240/(x+15) = 180/x 240x = 180(x+15) 4x = 3(x+15) x = 45 B goes 45, A goes 60 check: 240/60 = 180/45 = 4

Algebra help!!
you can always multiply by 1 without changing the value. So, you want something that makes the denominator rational. (3+?7)/(2-?7) * (2+?7)/(2+?7) = (3+?7)(2+?7) / (2-?7)(2+?7) = (13+5?7)/-3 (2-3i)/(6+i) * (6-i)/(6-i) = (2-3i)(6-i) / (6+i)(6-i) = (15-20i)/37

Math help
I always liked grace better ...

english
Thank you

english
Sorry, it's not letting me post my answer. I think it's (a)

english
Identify the sentence that is correctly punctuated. a. Our goal is simple: we aim to be the best in the industry. b. Our goal is simple, we aim to be the best in the industry. c. Our goal is simple—we aim to be the best in the industry. d. Our goal is simple: we aim to be...

english
Would it be d

english
. Identify the correct sentence. a. 3 CEOs will meet at the Regency Hotel tomorrow to discuss the possible merging of companies. b. Three CEOS will meet at the Regency hotel tomorrow to discuss the possible merging of companies. c. Three CEO’s will meet at the Regency ...

english

english
I'm trying to post b

english
Identify the sentence that is correctly punctuated. a. We stopped at several places during our drive up the East Coast: Savannah, Georgia, Charleston, South Carolina, Trenton, New Jersey, and Allentown, Pennsylvania. b. We stopped at several places during our drive up the East...

english
I'm trying to post a

english
Identify the sentence that is punctuated correctly. a. She wore an unusual, attractive dress. b. She wore an unusual, and attractive dress. c. She wore an unusual attractive dress.

english
. Identify the sentence that is punctuated correctly. a. “Come back here”! screamed the boy’s mother as he ran into the street. b. “Come back here!” screamed the boy’s mother. As he ran into the street. c. “Come back here” screamed the ...

english
Thank you very much for all your help.

english
Identify the correct sentence. a. Daniel’s science class starts at 7:30 am in the morning. b. Daniel’s science class starts at 7:30 a.m. c. Daniel’s Science class starts at 7:30 in the morning.

english
Not sure if my second answer went through. I think it's A

english
Would it be a

english
Identify the sentence that is correctly punctuated. a. Our goal is simple: we aim to be the best in the industry. b. Our goal is simple, we aim to be the best in the industry. c. Our goal is simple—we aim to be the best in the industry. d. Our goal is simple: we aim to be...

english
Identify the sentence that is punctuated correctly. a. Boston, Massachusetts played an important role in American history and politics. b. Boston, Massachusetts played an important role, in American history and politics. c. Boston, Massachusetts, played an important role in ...

english
his or her are singular, correct? Or are they looking for b?

english
Nobody on the Tri Rail seems to know ________ way around Miami. A) their B) his C) there D) his or her

english
. Choose the correct sentence. a. Us kids are to blame for the mess in the kitchen. b. Don’t talk to we teenagers about curfews. c. Cheryl, Doug, and myself went to the beach on Independence Day. d. He corrected himself immediately. e. The manager and myself will attend ...

geometry
since BD bisects ABC, the two halves are equal. So, 2(2x+22) = 8x solve for x, and then use that to find DBC = ABD.

Algebra 2
Still no ideas at all? What about the formula confuses you? D = rt, so r = D/t ...

Calculus
shift right 4: (x-4)^3 shrink vertically by a factor of 2: 1/2 (x-4)^3 shift up 5: 1/2 (x-4)^3 + 5 Better review your algebra 2 ...

Plzzz help
A: future perfect B: past perfect C: present perfect D: past time to review the verb forms ...

Math
(- 3 1/5) + (-6 1/2) = -16/5 - 13/2 = -32/10 - 65/10 ...

Math
good, but make that 7.2 hours ...

Math
half the perimeter is 500 one side is x, so the other is 500-x

Maths
The speed difference is 100 The first plane has a 1/2 hour head start, during which it went 150 miles. so, it will take 1.5 hours to catch up. ...

math
(2*3^2, 3^3, 2*3*5) = 3 3 is the only factor common to all three numbers.

math
If you really don't understand anything about the properties, I suggest google. If you search for "distributive property" you will find many explanations and examples. If it's still unclear, you really need to sit down with your teacher and get some in-person...

math
I'd guess distributive. Why?

Algebra and Geometey
it is the transformation needed to return to the original state. Just as an inverse function is what you need to get x. sqrt(x) and x^2 are inverses because (sqrt(x))^2 = sqrt(x^2) = x similarly, stretch by 2 and shift 8 up has the inverse transformation shift down 8 and ...

english
Choose the correct sentence. a. Him and I went through a lot together. b. My boss asked my coworker and I to stay late. c. Jennifer stormed out of the house and slammed the door because she and her mother got into an argument. d. Who should I send this email to?

english
Carolyn was thrilled when she found out her new employer offers two ________ vacation time. a. week’s b. weeks c. weeks’ d. week

english
Mr. ________ profit-and-loss report is due tomorrow. a. Jones’s b. Jones’ c. Joneses’ d. Jones

english
. Identify the sentence that is correctly punctuated. a. Word Processing and Excel: those are the technology job requirements. b. Word Processing, PowerPoint, and Excel, those are the technology job requirements. c. Word Processing and Excel; those are the technology job ...

Math
the amount of acid in the parts must add up to the amount in the final mix. If x ml of water (0% acid) are added, then you need .60*50 + 0x = .40(50+x) Now just solve for x. This assume you know what "%" means ...

Math
see related questions below.

math
well, you can start out by defining a and b. a = AB + BC/2 = AB - CB/2 b = AD + DC/2 = AD - CD/2 See what you can do with that, and AC = AB+BC BD = AD-BC

Math
first, list the scores in ascending order...

Math
yes.

Math
Clearly the center is at (-4,3) That means you have an ellipse with a = 6/2 = 3 b = 4/2 = 2, so its equation is (x+4)^2/3^2 + (y-3)^2/2^2 = 1

PreCalc
Draw a diagram, with the center of the base at (0,0) It is easy to see that the equation of the ellipse is x^2/55^2 + y^2/40^2 = 1 Now just find y when x=33

Math
If x cc are 40%, then the rest (25-x) is 10%. So, adding up the nutrient content, .40x + .10(25-x) = .16(25)

math
just take the average of the coordinates.. For x, that means (3 + -1)/2 = 2/2 = 1 Note that 1 is halfway from 3 to -1.

math
?y/?x = (3-3)/(2+6) = 0/8 = 0 Note that both points have the same y-coordinate, so the line is horizontal. Sometimes it pays to do a sanity check before diving into calculations,

I assume you want to solve these inequalities. Just do them the way you would work with equations. x - 7 > 10 add 7 to both sides: x > 17 3x <= 20 divide by 3: x <= 20/3 5a - 2 < 8 add 2, then divide by 5: 5a < 10 a < 2 2t + 8 >= 4(t + 1) 2t + 8 >= ...

Maths
cost: 990/1.10 and 990/0.90 so his income:cost ratio is (2*990)/(990/1.10 + 990/0.90) = 0.99 That is, a loss of 1%

Algebra, Trig
clearly the axle is 8m above the ground, and the radius is 4m. So, you can start out with a function that describes the distance to the ground. It will look something like h(t) = 4+4sin(t) See where you can go from there. I assume the platform is at the wheel's lowest point.

Math
well, 7^2 = 49 8^2 = 64 9^2 = 81 ...

Maths
angle B is 180-67-73 = 40° Now, using the law of sines 250/sin40° = PB/sin67°

Algebra
Try typing in your expression at wolframalpha.com and keep adding parentheses until it interprets your text correctly! I suspect you mean b - 2b/(b+3) ----------------- 1/(b+3) + 1/(b-3) If not, maybe you can clear things up a bit. Online text formatting requires a bit more ...

Math
What, you didn't try dividing 72440 by 9 to see whether it had no remainder? Geez! If a number is divisible by 9, so is the sum of its digits. 2+4+4=10, 1+0=1, so the missing digit is 8. 82440 = 9*9160

math / science
well, 512 = 2^9, so it has doubled 9 times...

Math
33+99+44 + 33*99 + 33*44 + 99*44 + 33*99*44 = 152999