Вправа 645 алгебра Бевз гдз 7 клас
№ 645
а) у3 – 2у2 – у + 2 = 0
y2(y – 2) – (y – 2) = 0
(y – 2)(y2 – 1) = 0
(y – 2)(y – 1)(y + 1) = 0
y1 = 2; y2 = 1; y3 = –1;
б) 2х3 – 3х2 + 8х = 12
x2(2x – 3) – 4(2x – 3) = 0
(2x – 3)(x2 – 4) = 0
(2x – 3)(x – 2)(x + 2) = 0
x1 = 1,5; x2 = 2; x3 = –2;
в) х2(2х + 1) – 4х(2х + 1) + 8х + 4 = 0
x2(2x + 1) – 4x(2x + 1) + 4(2x + 1) = 0
(2x + 1)(2x – 4x + 4) = 0
(2x + 1)(x – 2)2 = 0
x1 = –0,5; x2 = 2;
г) х3(х2 – 6х + 9) – 4х(х2 – 6х + 9) = 0
x(x2 – 6x + 9)(x2 – 4) = 0
x(x – 3)2(x – 2)(x + 2) = 0
x1 = 0; x2 = 3; x3 = 2; x4 = –2.
вправи поруч
