Can somebody good with math help me with this question?

Question

10x^-2 +33x^-1 -7=0...please sure your work and how you got the answer..it would be greatly appreciated

Answer 1

10x^-2 + 33x^-1 - 7 = 0
Let u = x^-1
10u^2 + 33u - 7 = 0
(2u+7)(5u-1) = 0
u = -7/2, 1/5
x = -2/7, 5

Answer 2

All righty buddy here's what i did...

First i rewrite the equation and put those negative exponents in the denominator (example: x^(-2) = 1/(x^2))

So the equation now becomes:

10/(x^2) + 33/x - 7 = 0

My next step is to try and put this into a form easier to solve, so what i want to do is bring all of those x's in the denominators back up to the numerator, but this time with positive exponents. So i multiply both sides of the equation by x^2 (using distributive laws). The resulting multiplication gives me this new equation:

10 + 33x - 7x^2 = 0

Then just because i like working with a positive constant in front of my x^2 term, i multiplied through by -1, and then reorder my terms to give:

7x^2 - 33x - 10 = 0


Now all that is left to do is factor and solve:


( 7x + 2 ) ( x - 5 ) = 0




x= - 2/7 x = 5


Good luck and boy are you lucky that I randomly stumbled upon Yahoo Answers for the first time ever ; - )

Answer 3

Multiply through by x^2 to get an ordinary quadratic:

-7x^2 + 33x + 10 = 0

Then use the quadratic equation to solve.

-2/7, 5

Answer 4

EDIT: Ah i skipped a step! read gp4rts's answer...then use the form i put.
Im sorry...all my work below is wrong (except for the formula)



its a quadratic equation. the formula for quadratics is...

-b plus or minus \/ b^2 - 4ac
-------------------------------------------
2a

(the V is supposed to be square root of b^2 - 4ac)
in this formula, a is 10, b is 33, and c is -7

insert the numbers

-33 plus or minus the square root of (33^2 minus 4(10)(-7)
-33 plus or minus the square root of (1089 minus -280
negative minus a negative is a addition...
(-33 plus or minus the square root of 1369) divided by 2(10)
square root of 1369 is 37

(-33 plus or minus 37) divided by 20
plus would make it 4 divided by 20
minus would make it negative 70

the answers would be x = 1/5 and x = -3.5
usually you use the positive answer, which in this case is
x = 1/5