1. Change the fraction w – 3 / w + 5 into an equivalent fraction with the denominator w^2 + w – 20.


A.w^2 + 7w – 12 / w^2 + w – 20.



B.w^2 – 7 – 12 / w^2 + w – 20



C.w^2 – 7w + 12 / w^2 + w – 20



D.w^2 + 7w + 12 / w^2 + w – 20

Verified Answer :

w^2 + w - 20 = (w + 5)(w - 4)

(w - 3)     (w - 4)      w^2 - 7w + 12
---------- * -------- =    ------------------
(w + 5)    (w - 4)        w^2 + w - 20

Answer:

C. \(\frac{w^2-7w+12}{w^2+w-20}\)

Step-by-step explanation:

We have been given a fraction \(\frac{w-3}{w+5}\) and we are asked to write the equivalent fraction of our given fraction with the denominator  \(w^2+w-10\).

First of all we will divide \(w^2+w-10\) by \(w+5\) to find the expression that we need to multiply with our given fraction to get the denominator \(w^2+w-10\)

Let us factor out \(w^2+w-10\) by splitting the middle term

\(w^2+w-10\)

\(w^2+5w-4w-20\)

\(w(w+5)-4(w+5)\)

\((w+5)(w-4)\)

\(\frac{w^2+w-20}{w+5}=\frac{(w+5)(w-4)}{(w+5)}=(w-4)\)

Now we will multiply the numerator and denominator of \(\frac{w-3}{w+5}\) by \((w-4)\) to find the equivalent fraction.

\(\frac{w-3}{w+5}*\frac{(w-4)}{(w-4)}\)

\(\frac{(w-3)*(w-4)}{(w+5)*(w-4)}\)

\(\frac{w^2-4w-3w+12}{w^2-4w+5w-20}\)

\(\frac{w^2-7w+12}{w^2+w-20}\)

Therefore, option C is the correct choice.