| If 2x + y -5 = 0 and the x + y – 13 = 0 then what is 4x

^{2}+ y^{2}+4xy equal toA. 24

B. 25

C. 21

D. 20

### Right Answer is: B

#### SOLUTION

Given equations are

2x + y = 5

x + y = 13

by solving both the equations

x = -8 and y = 21

now, 4x^{2} + y^{2} – 4xy = 4 (-8)^{2} + (21)^{2} + 4(-8)(21) = 256 + 441 – 672 = 25