习题3.5第1题答案
(1)4a-2(b-3c)
=4a-2b+6c
(2)-5a+(4x-6)/2
=-5a+2x-3
(3)3x+[4y-(7z+3)]
=3x+(4y-7z-3)
=3x+4y-7z-3
(4)-3a3-[2x2-(5x+1)]
=-3a3-(2x2-5x-1)
=-3a3-2x2+5x+1
习题3.5第2题答案
(1)(8x-5y)-(4x-9y)
=8x-5y-4x+9y
=4x+4y
(2)x-(2x-y)+(3x-2y)
=x-2x+y+3x-2y
=2x-y
(3)2(x+y)+(-5x+2y)
=2x+2y-5x+2y
=4y-3x
(4)(3a2-b2)-3(a2-2b2)
=3a2-b2-3a2+6b2
=5b2
(5)-2(-3xy+2z)+3(-2xy-5x)
=6xy-4z-6xy-15x
=-4z-15x