化简求值
(a+2)^-2(a+3)(a-2)+(a-3)^,其中a=-0.75
化简求值
(a+2)^-2(a+3)(a-2)+(a-3)^,其中a=-0.75
=a^2+4a+4-2a^2-2a-6+a^2-6a+9
=-4a+7
a=-0.75
-4a+7=(-4)*(-0.75)+7=10
(a+2)^-2(a+3)(a-2)+(a-3)^
=a^2+4a+4-2(a^2+a-6)+a^2-6a+9
=2a^2-2a+13-2a^2-2a+12
=-4a+25
所以当a=-0.75时,原式=-4*(-0.75)+25=28