Algebra

posted by .

How do I work this correctly? I know the answer is 7 but I am doing something wrong.Here is what I have...
x+ã(2x-5)=10
x+ã(2x-5)^2=10^2
x+2x-5=100
3x-5+5=100+5
3x=105
x=35
PLEASE HELP!

  • Algebra -

    what is the a~ all about? If it is a square root symbol then the solution looks like this:

    x + (2x-5)^(1/2) = 10 : move x to other side
    (2x-5)^(1/2) = 10 - x : square both sides
    2x-5 = (10-x)^2 : expand the squared term
    2x-5 = 100-10x-10x+x^2 : combine terms
    0 = 105 - 22x + x^2 : use quadratic formula to solve for x
    x =[-(-22) +/- sqrt(22^2 -4*1*105)]/(2*1)
    x= [22 +/- sqrt(484 - 420)]/2
    x= [22 +/- 8] / 2
    x= 7 or 15

    Plugging back into our initial equation shows that 7 is a solution, but 15 is not. This is because we started with a square root, which is invalid for negative numbers.

    Regards.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math help, correction

    Anna has 12 bills in her wallet, some $5 and some $10. The total value of the bills is $100. HOw many of each bill odes Anna have?
  2. math

    I am doing something wrong when I work this question. Can someone show me the steps. I have the answer. x<5.189 The sum of the costs in parts a and c is less than $120. Write and solve an inequality to determine the possiblities …
  3. Calculus

    The cost (in dollars) of producing x units of a certain commodity is c(x)=5000+10x+0.05x^2 Find A=100 to x=105 so far i got y-y/x-x= C(105)-C(100)/105-105 i don't understand how it comes out to be 101.25/5 please help me
  4. 8th Grade Algebra: Answer Check

    Find the length of the 3rd side of each right triangle. 1. 8^2+15^2=c^2 Answer: c=17 2. 5^2+b^2=13^2 Answer: b=12 3. 9^2+13^2=c^2 Answer: c~15.81 Simplify. Assume that all variables are nonnegative. { this means square root 4. {12 …
  5. statistics

    A professional basketball player has embarked on a program to study his ability to shoot foul shots. On each day in which a game is not scheduled, he intends to shoot 100 foul shots. He maintains records over a period of 40 days of …
  6. Pre-Algebra

    Can I have someone check this please? I wouldn't want to do the whole page, then find out I had done them all wrong. :( [Percents of Change] A $100 digital watch is now $72 Decrease, 72/100 = negative percent. 100/72.00 = .72 .72 -
  7. Math

    Solve the equation: 4x^2 + 100 = 0 Here is my work: 4x^2 + 100 = 0 - 100 - 100 4x^2 =0 /4 /4 x = -5 or 5. Did I do this correctly?
  8. 6th grade math

    Hi.. i'm a little confused on using proprtion equations to solve percent problem. can you check the following?
  9. Algebra 2

    Find the values of the 30th and 90th percentiles of the data. Please show your work. 129, 113, 200, 100, 105, 132, 100, 176, 146, 152
  10. Algebra2 Help please

    Find the values of the 30th and 90th percentiles of the data. Please show your work. 129, 113, 200, 100, 105, 132, 100, 176, 146, 152

More Similar Questions