Question

Как сделать проверку уравнения:
4(3y+1)^2 - 27=(4y+9)(4y-9)+2(5y+2)(2y-7)

Answer 1

4(3y + 1)² - 27 = (4y + 9)(4y - 9) + 2(5y + 2)(2y - 7)

4(9y² + 6y + 1) - 27 = 16y² - 81 + 2(10y² - 35y + 4y - 14)

36y² + 24y + 4 - 27 = 16y² - 81 + 20y² - 70y + 8y - 28

36y² + 24y + 4 - 27 - 16y² + 81 - 20y² + 70y - 8y + 28 = 0

86y + 86 = 0

86y = -86

y = -86/86 = -1

Проверка

4(3(-1) + 1)² - 27 = (4(-1) + 9)(4(-1) - 9) + 2(5(-1) + 2)(2(-1) - 7)

4(-3 + 1)² - 27 = (-4 + 9)(-4 - 9) + 2(-5 + 2)(-2 - 7)

4(9 - 6 + 1) - 27 = 16 + 36 - 36 - 81 + 2(10 + 35 - 4 - 14)

-11 = -65 + 20 + 70 - 8 - 28

-11 = -11

Answer 2

y = - 1