Question

1) 3(x-3)-4(x+5)=20
2) 5(x+4)-3(x-1)=25
3) (x-4) ²-x²=-6x+11

Answer 1

Ответ: лови)

Объяснение:

Answer 2

$\large1)3(x - 3) - 4(x + 5) = 20 \\ \\ \large 3x - 9 - 4x - 20 = 20 \\ \\ \large - x - 29 = 20 \\ \\ \large- x = 20 + 29 \\ \\ \large- x = 49~~~~\Rightarrow \:~~~~ \boxed{x = 49}$

$\large2)5(x + 4) - 3(x - 1) = 25 \\ \\ \large5x + 20 - 3x + 3 = 25 \\ \\ \large2x + 20= 25 \\ \\ \large2x = 25 - 23 \\ \\ \large2x = 2 \\ \\ \large \:x = 2 \div 2 ~~~\Rightarrow \:~~~ \boxed{x = 1}$

$\large3)(x - 4) {}^{2} - {x}^{2} = - 6x + 11 \\ \\ \large ( {x}^{2} - 2 \cdot \: x \cdot4 + {4}^{2}) - {x}^{2} = - 6x + 11 \\ \\ \large {x}^{2} - 8x + 16 - {x}^{2} = - 6x + 11 \\ \\ \large - 8x + 16 = - 6x + 11 \\ \\ \large - 8 + 6x = 11 - 16 \\ \\ \large - 2x = - 5 \\ \\ \large - x = - 5 \div ( - 2) \\ \\ \large - x = - 2.5~~~\Rightarrow \:~~~ \boxed{x = 2.5}$