Question

If a^2−b^2=2352 and a^2+b^2=14210 then what is the value of 13ab?

Answer 1

a^2 = 2352 + b^2 --- 1
Sub 1 in a^2+b^2=14210 --- 2
2352 + 2b^2 = 14210
b = 77 ---- 3
Sub 3 in 1
a = 91
13ab = 13 × 91 × 77 = 91091.