先化简,再求值(2a+1)(2a-1)-(2a-3)(3a+1),其中a=-2分之1
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先化简,再求值(2a+1)(2a-1)-(2a-3)(3a+1),其中a=-2分之1
先化简,再求值(2a+1)(2a-1)-(2a-3)(3a+1),其中a=-2分之1
先化简,再求值(2a+1)(2a-1)-(2a-3)(3a+1),其中a=-2分之1
(2a+1)(2a-1)-(2a-3)(3a+1)
=4a^2-1-6a^2+7a+3
=-2a^2+7a+2 a=-1/2
=-2(-1/2)^2-7/2+2
=-4+2
=-2
(2a+1)(2a-1)-(2a-3)(3a+1)
=4a²-1-(6a²-7a-3)
=4a²-1-6a²+7a+3
=-2a²+7a+2
=-2×1/4-7/2+2
=-2
(2a+1)(2a-1)-(2a-3)(3a+1)
=(4a²-1)-(6a²+2a-9a-3)
=4a²-6a²+7a+3-1
=-2a²+7a+2
=-2×(1/4)+7×(-1/2)+2
=-1/2-7/2+2
=-2
(2a+1)(2a-1)-(2a-3)(3a+1)
=(4a^2-1)-(6a^2-7a-3)
=-2a^2+7a+2
=-2*1/4-7/2+2
=-4+2
=-2