- #1

supermath

- 16

- 0

- Homework Statement:
- Solve the equation.

- Relevant Equations:
- x(7x-8)=15

I do

7x^2-8x=15

7x^2-8x-15=0

I turn the problem into a Grouping(4 term) problem by multiplying 7*(-15) = 105

I find what numbers multiply to -105 and add to -8. -15 and 7 multiply to -105 and add to -8.

7x^2-15x+7x-105=0

I group them.

7x^2-15x | 7x-105=0

This is where i get lost, because i get

7x(x-1\2)*7(x-15)

The numbers in parenthesis are suppose to match.

7x^2-8x=15

7x^2-8x-15=0

I turn the problem into a Grouping(4 term) problem by multiplying 7*(-15) = 105

I find what numbers multiply to -105 and add to -8. -15 and 7 multiply to -105 and add to -8.

7x^2-15x+7x-105=0

I group them.

7x^2-15x | 7x-105=0

This is where i get lost, because i get

7x(x-1\2)*7(x-15)

The numbers in parenthesis are suppose to match.

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