Question

Find the following products using the identity: (x + a) (x + b) = x + (a + b) x + ab.
(x + 15) (x-6)​

Answer 1

Step-by-step explanation:

Solution

(x+a)(x+b)=x2+(a+b)x+ab

(i) (x+2)(x+3)

=x2+(2+3)x+2×3

=x2+5x+6

(ii) (x−10)(x+8)

=x2+(−10+8)x+(−10)×8

=x2−2x−80

(iii) (x+15)(x−6)

=x2+(15−6)x+15×(−6)

=x2+9x−90

(iv) (x+7)(x+7)

=x2+(7+7)x+7×7

=x2+14x+49