问题
解答题
用心解一解. (1)计算:2.4-(-
(2)计算:(-3)2-(
(3)先化简再求值,其中a=-1,b=1:(5a2-3b2)+(a2+b2)-(5a2+3b2) (4)解方程:2(x-
(5)解方程:
|
答案
(1)原式=2.4+0.6-3.1+0.8=0.7;
(2)原式=9-
×27 8
-6÷2 9
=-2 3
;3 4
(3)原式=5a2-3b2+a2+b2-5a2-3b2=-4a2,
当a=-1时,原式=-4;
(4)去括号得:2x-1=x+4,
解得:x=5;
(5)去分母得:2(3x-1)=10-5(x+2),
去括号后得:6x-2=10-5x-10,
解得:x=
.2 11