Question

If a + b = 4 and ab = -12, find (i) a - b (ii) a2 - b2.​

Answer 1

Answer:

(i)(a-b)²=(a+b)²-4ab

(a-b)²=16+48

(a-b)²=64

a-b=8

(ii) a²-b²=(a-b)²+2ab

a²-b²=64-24

a²-b²=40

Step-by-step explanation:

Answer 2

Step-by-step explanation:

Given, a+b=4

ab= -12

we know that,

(a+b)^2=a^2+ b^2+ 2ab

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

=(4)^2-2×(-12)

=16-(-24)

=16+24

=40

Now,(a-b)^2=a^2+b^2-2ab

(a-b)=root over a sq. +b sq. -2ab

=root over 40-2(-12)

=root over 40+24

=root over 64

=+ 8

hence,(a-b)=+ 8