Question

If a-
b=7 and ab=18 find the value of a+b

Answer 1

There are two methods to solve this question.

1st one is by hit and trial as we know ab=18

Product of two numbers ie 18 are 6x3 & 9x2

Putting these in equation a-b=7 ,9&2 satisfy this equation and hence the answer.

2nd Method

a-b=7 & ab=18 ,,we will find value of a+b

(a+b)^2 = (a-b)^2 +4ab

(a+b)^2 = 49 +4x18

(a+b)^2= 121

(a+b) = 11

Now solving both equations ,a=9 &b=2