Question

if3x-4y=16andxy=4,findthevalueof9x2+16y2

Answer 1

it is power 2 in last

Answer 2

given xy =4
So x/y=4 or y=4/x
put y=4/x in 3x-4y=16
3x-16/x=16
take LCM
3x^2-16=16
3x^2-16x-16=0
solving the eqn
(3x-4)(x-4)=0
x=4/3 or 4
taking the whole number (x=4)
9(4^2)+16(1^2)= 160