Question

Решите уравнение:
2$x^{2} + 3x = 2 x^{2} + 21$
$(3x+1)(4x-5)=12 x^{2} - 13x +1$
Упростить выражение:
$(2x-3)(3x+7)-(x-5)=12 x^{2} -13x+1$ при x = 11

Answer 1

2x^2+3x = 2x^2+21
3x = 21
x = 7

(3x+1)(4x-5) = 12x^2-13x+1
12x^2-11x-5 = 12x^2-13x+1
2x = 6
x = 3

(2x-3)(3x+7)-(x-5) = 12x^2-13x+1
6x^2+14x-9x-21-x+5 = 12x^2-13x+1
-6x^2+17x = 17
x(17-6x) = 17