Question

expand it in the formula (x+a)(x+b)=x2+(a+b)x+ab
(a+2)(a_1)

Answer 1

do you want to know the formula?

Answer 2

( x+a) (x+b) = x² + (a+b)x + ab

Here,

a= 2, b = -1, x= a

( x+a) (x+b) = x² + (a+b)x + ab

(a+2)(a-1) = a² + ( 2+(-1) )a + 2*-1

a² + (2-1) a -2

a² +a - 2

Hope it helps.