Câu 1:a.2x2 - 3x - 2 = 2x2 - 4x + x - 2 = (2x2 - 4x) + (x - 2)= 2x(x - 2) + (x - 2) = (x - 2)(2x + 1)b.4x(x - 2) + 3(2 - x) = 4x(x - 2) - (x - 2) = (x - 2)(4x - 1)c.27x3 + 8 = (3x)3 + 23 = (3x + 2)[(3x)2 - 2.3x + 22] = (3x + 2)(9x2 - 6x + 2)d.x2 + 2x - y2 + 1 = (x2 + 2x + 1) - y2 = (x + 1)2 - y2= (x + 1 - y)(x + 1 + y)

A.2X2 - 3X - 2 = 2X2 - 4X + X - 2 = (2X2 - 4X) + (X - 2)= 2X(X - 2) +...

Lớp 8 Toán Đề thi giữa học kì 1 Toán lớp 8 năm 2021 - 2022 có đáp án (4 đề)

Câu 1:a.2x

- 3x - 2 = 2x

- 4x + x - 2 = (2x

- 4x) + (x - 2)= 2x(x - 2) + (x - 2) = (x - 2)(2x + 1)b.4x(x - 2) + 3(2 - x) = 4x(x - 2) - (x - 2) = (x - 2)(4x - 1)c.27x

+ 8 = (3x)

+ 2

= (3x + 2)[(3x)

- 2.3x + 2

] = (3x + 2)(9x

- 6x + 2)d.x

+ 2x - y

+ 1 = (x

+ 2x + 1) - y

= (x + 1)

- y

= (x + 1 - y)(x + 1 + y)