# How do you simplify #(x^2 – 6x + 5)/(x^2 – 25)#?

##### 1 Answer

Jun 10, 2016

#### Explanation:

To simplify we need to factorise both numerator and denominator.

NumeratorWe require to find 2 numbers which multiply to give +5 and at the same time sum to give -6 , the coefficient of the x term.

The numbers which multiply are 1 , 5 and -1 ,-5 and the only pair that sum to give -6 are -1 ,-5.

#rArrx^2-6x+5=(x-5)(x-1)#

DenominatorHere we have a

#color(blue)"difference of squares"# In general :

#color(red)(|bar(ul(color(white)(a/a)color(black)(a^2-b^2=(a-b)(a+b))color(white)(a/a)|)))# here a = x and b = 5

#rArrx^2-25=(x-5)(x+5)#

#rArr(x^2-6x+5)/(x^2-25)=((x-5)(x-1))/((x-5)(x+5))#

#=(cancel((x-5)) (x-1))/(cancel((x-5)) (x+5))=(x-1)/(x+5)#