Question

How do you simplify –2(x–9)+4(x+6)?

Answer 1

Answer:

$\sf - 2x(x - 9) + 4(x + 6) \\ \\ \sf - 2x^{2} + 18x + 4x + 24 \\ \\\sf - 2x {}^{2} + 22x + 24 = 0 \\ \\ \sf - 2(x {}^{2} - 11x - 12) = 0 \\ \\ \sf x {}^{2} - 11x - 12 = 0 \\ \\ \bf on \: splitting \: its \: middle \: term : \\ \\\sf x {}^{2} - 12x + x - 12 = 0 \\ \\\sf x(x - 12) - 1(x - 12) = 0\\ \\ \sf (x - 12)(x - 1) = 0 \\ \\ \boxed{ \bf x = 12 \: or \: x = 1}$

Answer 2

Answer:

2x + 42 or 2(x+21)

Step-by-step explanation:

-2(x-9) = -2x+18            -------- 1

4(x+6) = 4x+24             -------- 2

1 + 2

-2x+18 + 4x+24 = 2x + 42 or 2(x+21)