1/2（m-n) + 1/4(m+n) + m + n/3 - m - n/6
= 1/2m - 1/2n + 1/4m + 1/4n + m + n/3 - m - n/6
=(1/2m + 1/4m + m - m) + [(-1/2n + 1/4n) +（ n/3 - n/6)]
= 3/4m + (-1/4n + 1/6n)
= 3/4m -1/12n
把m=-9 n=-3代入1/2（m-n)+1/4(m+n)+m+n/3-m-n/6可得
1/2[ -9 -（-3）] + 1/4（-9-3）+（-9）-3/3 -（-9）-（-3/6）
= 3/4m -1/12n
= 3/4 * (-9) - 1/12 * (-3)
= -27/4 + 1/4
= -26/4
= -13/2
1/2（2x的2次方-6x-4)-4(-1+x+1/4x的2次方）
= 1/2(2x^2 - 6x - 4) - 4(-1 + x + 1/4x^2)
= 1/2 * 2x^2 - 1/2 *6x - 1/2 * 4 - 4 * (-1) - 4 * x - 4 * 1/4x^2
= x^2 - 3x - 2 + 4 - 4x - x^2
= (x^2 - x^2) + (- 3x - 4x)- 2 + 4
= -7x + 2
把 x = 5 代入上式可得
1/2（2x的2次方-6x-4)-4(-1+x+1/4x的2次方）
= -7x + 2
= -7 * 5 + 2
= -33