Question

if a^2 + b^2 = 9 and ab=4 find the value of 3( a+ b )^2 - 2 (a-b)2

Answer 1

3(a+b)^2-2(a-b)^2
3(a^2+b^2+2ab)-2(a^2+b^2-2ab)
a^2+b^2+10ab=9+10×4=49

hope it helps you

Answer 2

firstly , ab=4 ....... 2nd equation
a=4/b
put this value in your 1st equation
and u get the value b
after do that put the value of b in equation 2nd
so u get a and b
put the value of a and b in your last equation