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计算.求-2(10a^2-2ab+3b^2)+3(5a^2-4ab+3b^2)的值,其中a=1,b=-2

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计算.求-2(10a^2-2ab+3b^2)+3(5a^2-4ab+3b^2)的值,其中a=1,b=-2
1 求-2(10a^2-2ab+3b^2)+3(5a^2-4ab+3b^2)的值,其中a=1,b=-2
2 (-32)X(-1/32)-(1/2+2/3-3/4-11/12)X24
计算.求-2(10a^2-2ab+3b^2)+3(5a^2-4ab+3b^2)的值,其中a=1,b=-2
解-2(10a^2-2ab+3b^2)+3(5a^2-4ab+3b^2)
=-20a^2+4ab-6b^2+15a^2-12ab+9b^2
=-5a^2-8ab+3b^2
由a=1,b=-2
即-5a^2-8ab+3b^2
=-5-8b+3b^2
=-5-8*(-2)+3(-2)^2
=-5+16+12
=23
(-32)X(-1/32)-(1/2+2/3-3/4-11/12)X24
=1-(1/2+2/3-3/4-11/12)X24
=1-1/2X24-2/3X24+3/4X24+11/12X24
=1-12-16+18+22
=1-28+18+22
=1-10+22
=13