计算题:(1)-24÷(-14)×(-7);(2)3×(-9)-(-15)×(-3)-3×18;(3)(5a2-3b2)-[(a2-2ab-b2)-(5a2-2
题型:解答题难度:一般来源:不详
计算题: (1)-24÷(-14)×(-7); (2)3×(-9)-(-15)×(-3)-3×18; (3)(5a2-3b2)-[(a2-2ab-b2)-(5a2-2ab-3b2)]; |
答案
(1)-24÷(-14)×(-7)=-16×(-)×(-7)=-8;
(2)3×(-9)-(-15)×(-3)-3×18 =3×(-9-15-18) =3×(-42) =-126;
(3)(5a2-3b2)-[(a2-2ab-b2)-(5a2-2ab-3b2)] =5a2-3b2-[a2-2ab-b2-5a2+2ab+3b2] =5a2-3b2-a2+2ab+b2+5a2-2ab-3b2 =9a2-5b2. |
举一反三
式子(x2-2y)+(x-y2)-(x2+y2)=______. |
先化简,再求值:2(5a2-7ab+9b2)-3(14a2-2ab+3b2),其中a=,b=-. |
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