Question

If (a-b)=0.9 and ab =0.36, find the value of
1) (a+b)
2) (a²-b²)
Answers are 1.5 and 1.35

Answer 1

Answer:

1.5,1.35

a-b=0.9

ab=0.36

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

(0.9)^2=a^2+b^2-2(0.36)

a^2+b^2=1.53

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

(a+b) ^2=1.53+0.72

a+b=1.5

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

=1.5×0.9

=1.35