Question #6a4c5

1 Answer
Feb 4, 2017

y^2 - 22y + 121 = (y - 11)(y- 11)y222y+121=(y11)(y11)

Explanation:

y^2 -22y+121y222y+121

By splitting the middle term i.e. -22 in such a way so, that the sum of those two numbers would be -22 and their product would be 121. Therefore, these two numbers are -11 and -11 . Here, both conditions are applied.

y^2 - 11y - 11y + 121y211y11y+121

y(y - 11) - 11(y -11)y(y11)11(y11)

(y - 11)(y- 11)(y11)(y11)

Alternative Method:

y^2 - 22y + 121y222y+121

By using the identity -

(a - b)(a - b) = a^2 - 2ab + b^2(ab)(ab)=a22ab+b2

Here , a = y , b = 11a=y,b=11

(y)^2 - 2(y)(11) + (11)^2(y)22(y)(11)+(11)2

(y - 11)(y -11)(y11)(y11)