作业帮a的平方+2a-8=0,a(a+2)的平方-a(a-3)(a-1)+3(5a-2)等于多少?
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/16 14:24:34
a的平方+2a-8=0,a(a+2)的平方-a(a-3)(a-1)+3(5a-2)等于多少?
a的平方+2a-8=0,a(a+2)的平方-a(a-3)(a-1)+3(5a-2)等于多少?
a的平方+2a-8=0,a(a+2)的平方-a(a-3)(a-1)+3(5a-2)等于多少?
a的平方+2a-8=0
a²+2a=8
a(a+2)的平方-a(a-3)(a-1)+3(5a-2)
=a(a²+4a+4)-a(a²-4a+3)+15a-6
=a(a²+4a+4-a²+4a-3)+15a-6
=8a²+a+15a-6
=8(a²+2a)-6
=8×8-6
=58
a^2+2a-8=0
a^2+2a=8
a(a+2)^2-a(a-3)(a-1)+3(5a-2)
=a(a^2+4a+4)-a(a^2-4a+3)+3(5a-2)
=a(a^2+4a+4)-a(a^2-4a+3)+3(5a-2)
=a(a^2+2a+2a+4)-a(a^2+2a-6a+3)+3(5a-2)
=a(8+2a+4)-a(8-6a+3)+3(5a-2)
=a(2a+12)-a(-6a+11)+3(5a-2)
=2a^2+12a+6a^2-11a+15a-6
=8a^2+16a-6
=8(a^2+2a)-6
=8*8-6
=64-6
=58
a的平方+2a-8=0
(a-2)(a+4)=0
a=2或a=-4
当a=2
a(a+2)的平方-a(a-3)(a-1)+3(5a-2)
=32+2+24
=58
当a=-4
a(a+2)的平方-a(a-3)(a-1)+3(5a-2)
=-16+140-66
=58
a^2+2a-8=0
(a+4)(a-2)=0
a=-4 a=2
(1)当a=-4时
a(a+2)^2-a(a-3)(a-1)+3(5a-2)
=-4*(-4+2)^2-(-4)*(-4-3)(-4-1)+3(5*(-4)-2)
=-4*2^2-(-4)*(-7)(-5)+3(-20-2)
=-16+140-66
=58
(2)当a=2时
a(a+2)^2-a(a-3)(a-1)+3(5a-2)
=2*(2+2)^2-2*(2-3)(2-1)+3(5*2-2)
=32+2+24
=58