Question

Se x+y=4 o valor de x^2+2xy+y^2 quanto é?

Answer 1

x+y = 4
x²+2xy+y² = (x+y)² = 4² = 16

Answer 2

X+Y=4    X=4-Y        Y=4-X
O VALOR DE X²+2XY+Y²
                (4-Y)²+2.(4-Y).(4-X)+(4-X)²
        4²-2.4.Y+Y²+2(16-4X-4Y+XY)+4²-2.4.X+X²
       16-8Y+Y²+32-8X-8Y+2XY+16-8X+X²
Y²+X²-8Y-8Y--8X-8X+2XY+16+16+32
Y²+X²-16Y-16X+2XY+64