2017年春浙教版七年级数学下册同步练习（PDF版）:4.1 因式分解

4.1 因式分解 一、选择题 1.下列等式从左边到右边的变形，属于因式分解的是 ( ) A. 2ab (a− b) = 2a2b− 2ab2 B. x2 + 1 = x ( x+ 1 x ) C. x2 − 4x+ 3 = (x− 2)2 − 1 D. a2 − b2 = (a+ b) (a− b) 2. 下列式子从左到右的变形中是分解因式的为 ( ) A. y2 − 3y − 4 = y (y − 3)− 4 B. 1− 4x+ 4x2 = (1− 2x)2 C. x2 + y2 = (x+ y) (x− y) D. x− 1 = x ( 1− 1 x ) 3.下列分解因式正确的是 ( ) A. x3 − x = x (x2 − 1) B. x2 − x+ 2 = x (x− 1) + 2 C. x2 + 2x− 1 = (x− 1)2 D. x2 − 1 = (x+ 1) (x− 1) 4.下列各式自左到右的变形属于因式分解的是 ( ) A. m (a+ b+ c) = ma+mb+mc B. x2 + 1 y2 = Å x+ 1 y ãÅ x− 1 y ã + 2 y2 C. x2 − y2 + 4x+ 4 = (x+ y) (x− y) + 4 (x+ 1) D. − 1 2 a2 + 2b2 = − 1 2 (a+ 2b) (a− 2b) 5. 下列各式从左到右的变形为分解因式的是 ( ) A. m2 −m− 6 = (m+ 2) (m− 3) B. (m+ 2) (m− 3) = m2 −m− 6 C. x2 + 8x− 9 = (x+ 3) (x− 3) + 8x D. 18x3y2 = 3x3y2 · 6 6. 下列变形是因式分解的是 ( ) A. x2 + 6x+ 8 = x (x+ 6) + 8 B. (x+ 2) (x− 2) = x2 − 4 C. x2 + 3x = x2 ( 1 + 3 x ) D. x2 − 3x+ 2 = (x− 1) (x− 2) 7.下列式子中，从左到右的变形为多项式因式分解的是 ( ) A. x2 − 2 = Ä x+ √ 2 ä Ä x− √ 2 ä B. Ä x+ √ 2 ä Ä x− √ 2 ä = x2 − 2 C. x− 4 = ( √ x+ 2) ( √ x− 2) D. ( √ x+ 2) ( √