Question

2x + 3 . X+1 = 2x . X+3

Answer 1

$(2x+3)(x+1) = 2x(x+3)\\\\ aplicando\;as\;distributivas, temos\\\\ 2x^2+5x+3 = 2x^2+6x\\\\ reduzindo\;a\;termos\;semelhantes\\\\ 2x^2-2x^2 +5x- 6x = -3\\ -x = -3 \Longrightarrow (-1)\cdot(-x)=(-1)\cdot(-3)\\\\ \framebox[1.5\width]{x = 3}$

Answer 2

2x + 3 (x + 1) = 2x (x + 3)
2x + 3x + 3 = 2x² + 6x
-2x² + 2x + 3x - 6x + 3 = 0
-2x² - x + 3 = 0

a = -2; b = -1; c = 3

x = [- b ± √(b² - 4ac)] / 2a
x = [- (-1) ± √([-1]² - 4 . [-2] . 3)] / 2 . (-2)
x = [1 ± √(1 + 24)] / -4
x = [1 ± √25] / -4
x = [1 ± 5] / -4
x' = [1 - 5] / -4 = -4 / -4 = 1
x'' = [1 + 5] / -4 = 6 / -4 = -1,5

Espero ter ajudado. Valeu!