Thực hiện phép tính
a. (1/2 x – 1)(2x – 3)
b. (x – 7)(x – 5)
c. (x - 1/2 )(x + 1/2 )(4x - 1)
a. (1/2 x – 1) (2x – 3)
= x2 - 3/2 x – 2x + 3
= x2 - 7/2 x + 3
b. (x –7)(x –5)
= x2 – 5x – 7x + 35
= x2 – 12x + 35
c. (x - 1/2 )(x + 1/2 )(4x - 1)
= (x2 + 1/2 x - 1/2 x - 1/4 )(4x - 1)
= (x2 - 1/4 )(4x - 1)
= 4x3 – x2 – x + 1/4
-- Mod Toán 8
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