Phân tích thành nhân tử:
a. x2 + 5x – 6
b. 5x2 + 5xy – x – y
c. 7x – 6x2 – 2
a. x2 + 5x – 6 = x2 – x + 6x – 6 = (x2 – x) + 6(x – 1)
= x(x – 1) + 6(x – 1) = (x – 1)(x + 6)
b. 5x2 + 5xy – x – y = (5x2 + 5xy) – (x + y)
= 5x(x + y) – (x + y) = (x + y)(5x – 1)
c. 7x – 6x2 – 2 = 4x – 6x2 – 2 + 3x = (4x – 6x2) – (2 – 3x)
= 2x(2 – 3x) – (2 – 3x) = (2x – 1)(2 – 3x)
-- Mod Toán 8
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