帮我解下几道方程7.9(x+2)-1=0.1(x+2)2y-1/4=1-3-y/885%(2x-3)-55%(5-3x)=60%(5-3x)
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帮我解下几道方程7.9(x+2)-1=0.1(x+2)2y-1/4=1-3-y/885%(2x-3)-55%(5-3x)=60%(5-3x)
帮我解下几道方程
7.9(x+2)-1=0.1(x+2)
2y-1/4=1-3-y/8
85%(2x-3)-55%(5-3x)=60%(5-3x)
帮我解下几道方程7.9(x+2)-1=0.1(x+2)2y-1/4=1-3-y/885%(2x-3)-55%(5-3x)=60%(5-3x)
第一题
7.9(x+2)-1=0.1(x+2)
7.9x+15.8-1=0.1x+0.2
7.9x+14.8=0.1x+0.2
7.8x=-14.6
x=-2
第二题
2y-1/4=1-3-y/8 两边同时乘以8
得 16y-2=8-24-y
得 17y=-14
y=-14/17
第三题
85%(2x-3)-55%(5-3x)=60%(5-3x)
85%(2x-3)=60%(5-3x)+55%(5-3x)
85%(2x-3)=115%(5-3x)
85%/115%=(5-3x)/(2x-3)
17/23=(5-3x)/(2x-3)
17(2x-3)=23(5-3x)
34x-51=115-69x
103x=166
x=166/103
7.9(x+2)-1=0.1(x+2) 打开,再移项,7.8x=15,x=25/13 2y-1/4=1-3-y/8 移项,17y/8=-7/2,y=-28/17 85%(2x-3)-55%(5-3x)=60%(5-3x) 打开,移项,1.55x=8.3,x=166/31
7.9x+15.8=0.1x+0.2
7.8x=-15.6
x=2
2y+y/8=1-3+1/4
17/8y=-7/4
y=14/17
0.85(2x-3)-0.55(5-3x)=0.6(5-3x)
1.7x-2.25-2.75+1.65x=3-1.8x
5.15x=8
x=1.56