How do you evaluate $\frac { 5x + 15} { x ^ { 2} + 2x - 3} \cdot \frac { 7x - 7} { 10x + 20}$ ?

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Answer 1 · 2017-10-20T18:29:51

$3.5/(x+2)$

You can't evaluate for $x$ , but you can simplify this expression using factoring and dividing away numbers:

First factor:

$(5(x+3))/((x+3)(x-1))*(7(x-1))/(10(x+2))$

Multiply across:

$(5(x+3)7(x-1))/((x+3)(x-1)10(x+2))$

Divide away equivalent factors:

$(5cancel((x+3))7cancel((x-1)))/(cancel((x+3))cancel((x-1))10(x+2))$

Thus we are left with:

$35/(10(x+2))=3.5/(x+2)$

How do you evaluate \frac { 5x + 15} { x ^ { 2} + 2x - 3} \cdot \frac { 7x - 7} { 10x + 20}\frac { 5x + 15} { x ^ { 2} + 2x - 3} \cdot \frac { 7x - 7} { 10x + 20}?