Question

If a - b = 7 and ab = 18; find a + b.​

Answer 1

Answer:

a-b=7;a=7+b

so ab=18

b^2+7b-18=0(solve quadratic equation)

b= -9 or b=2

Now,

we know ab=18 substitute value of b

ab=18                    or          ab=18

a*-9=18                  or         a*2=18

-9a=18                   or          a=18/2

a=-2                       or           a=9

therfore,

a-b=7

so if we verify from this stament  a=9 and b=2

a+b=9+2=11