Question

9.Multiply:
(i)(a+5)by(a+4)
(ii)(x-3)by(x+8)
(iii)(2+1)by(z-7)​

Answer 1

Answer:

(a+5)(a+4)= a²+9a+20

Step-by-step explanation:

(a+5)(a+4)

= a²+(5+4)a+(5×4)

I

By algebraic identity:

(x+m)(x+n) = x²+(m+n)x+mn */

= a²+9a+20

Therefore,

(a+5)(a+4)= a²+9a+20

ii i don't know

iii 2^2-6Z-7

Step-by-step explanation:

=(2+1)(z-7)

=2(2-7)+1(2-7) =z^2-7+z-7

=2^2-6Z-7