1
a) (x+4)²-6x = x²+8x+16-6x = x²+2x+16.
b) (5x-1)(3x+4)-23(x-2) = 15x²+20x-3x-4-23x+46 = 15x²-6x+42.
2
а) 9x²-6xy+y² = (3x-y)².
b) 6x³c-3x²m = 3x²(2xc-m).
c) x(a+5)-7(a+5) = (a+5)(x-7).
3
2x-⁵/₄ = 3x+²/₃
2x-3x = ²/₃+⁵/₄
-x = ⁸/₁₂+¹⁵/₁₂
-x = ²³/₁₂
x = -1¹¹/₁₂
Ответ : -1¹¹/₁₂.