Question

Arme as operações. Por favor

A) x(x+4)+x(x+2)=2x²+12


B) (x-5) /10+(1-2x) /5+(3-x) /4


C) 4x(x+6)-x²=5x²

Answer 1

$a) \\ \\ x(x + 4) + x(x + 2) = 2x^2 + 12 \\ \\ x^2 + 4x+ x^2 + 2x = 2x^2 + 12 \\ \\ x^2 + x^2 - 2x^2 + 4x + 2x = 12 \\ \\ 6x = 12 \\ \\ \\ x = \dfrac{12}{6} \\ \\ => x = 2$

====

$b) \\ \\ (x - 5) / 10 + (1 - 2x) / 5 + (3-x)/4 \\ \\ (x - 5) / 10 - (13 - 19)/20 \\ \\ - (11x - 9) / 20 \\ \\ -11x - 9 (-1) \\ \\11x + 9 = 0 \\ \\ 11x = -9 \\ \\ \\=> x = \dfrac{9}{11}$

====

$c) \\ \\ 4x(x + 6) - x^2 = 5x^2 \\ \\ 4x^2 + 24x - x^2 = 5x^2 \\ \\ 3x^2 + 24x = 5x^2 \\ \\ 3x^2 + 24x - 5x^2 \\ \\=> -2x^2 + 24x = 0$