(1)(x+1)²+2(1-x)-x²(2)(a+2)(a-2)-a(a+1)(3)(a+3)²+a(2-a)(4)(a+b)²+a(a-2b)

问题描述:

(1)(x+1)²+2(1-x)-x²
(2)(a+2)(a-2)-a(a+1)
(3)(a+3)²+a(2-a)
(4)(a+b)²+a(a-2b)

(1)、(3a?? - 4) - (2a?? - 5a + 4) + (2a - a??)= 3a?? - 4 - 2a?? + 5a - 4 + 2a - a??= 7a - 8原式 = 7×(-1) - 8 = -15 (2)、-2m - {4m - 3n - [2m - (2n + 1)]}= -2m - 4m + 3n + [2m - (2n + 1)]= -2m - 4m + 3n + 2m - 2n - 1= -4m + n - 1原式 = -4×(-3) - 2 - 1 = 9

(1) 3
(2)-4-a
(3)8a+9
(4) 2a²+b²