SOLUTION: Please help with this question: 10x^2+5x^-30x Thanks in advance

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Question 699921: Please help with this question: 10x^2+5x^-30x
Thanks in advance
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for x:


Starting with the general quadratic


ax%5E2%2Bbx%2Bc=0


the general solution using the quadratic equation is:


x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29




So lets solve 10%2Ax%5E2%2B5%2Ax-30=0 ( notice a=10, b=5, and c=-30)





x+=+%28-5+%2B-+sqrt%28+%285%29%5E2-4%2A10%2A-30+%29%29%2F%282%2A10%29 Plug in a=10, b=5, and c=-30




x+=+%28-5+%2B-+sqrt%28+25-4%2A10%2A-30+%29%29%2F%282%2A10%29 Square 5 to get 25




x+=+%28-5+%2B-+sqrt%28+25%2B1200+%29%29%2F%282%2A10%29 Multiply -4%2A-30%2A10 to get 1200




x+=+%28-5+%2B-+sqrt%28+1225+%29%29%2F%282%2A10%29 Combine like terms in the radicand (everything under the square root)




x+=+%28-5+%2B-+35%29%2F%282%2A10%29 Simplify the square root (note: If you need help with simplifying the square root, check out this solver)




x+=+%28-5+%2B-+35%29%2F20 Multiply 2 and 10 to get 20


So now the expression breaks down into two parts


x+=+%28-5+%2B+35%29%2F20 or x+=+%28-5+-+35%29%2F20


Lets look at the first part:


x=%28-5+%2B+35%29%2F20


x=30%2F20 Add the terms in the numerator

x=3%2F2 Divide


So one answer is

x=3%2F2




Now lets look at the second part:


x=%28-5+-+35%29%2F20


x=-40%2F20 Subtract the terms in the numerator

x=-2 Divide


So another answer is

x=-2


So our solutions are:

x=3%2F2 or x=-2