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