玫瑰花酱怎么吃:初一数学题,各位姐姐哥哥帮帮忙吧~~~~
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2(X-8)(X+5)-(2X-1)(X+2)其中,X=-7
先化简,再求值(要具体过程哦~~~)
先化简,再求值(要具体过程哦~~~)
=2(x^2-8x+5x-40)-(2x^2+4x-x-2)
=2x^2-6x-80-2x^2-3x+2
=-9x-78
=63-78
=-15
=2(x^2-8x+5x-40)-(2x^2+4x-x-2)
=2x^2-6x-80-2x^2-3x+2
=-9x-78
=63-78
=-15