x+7/2=1/5x+11.5

x+7/2=1/5x+11.5


x+7/2=1/5x+11.5
移項
x-0.2x=11.5-2.5
0.8x=9
x=90/8=11.25



1-3/5x(1/2-5/3)/7/4


1-3/5x(1/2-5/3)/7/4
=1-3/5x(-7/6)x4/7
=1+7/10x4/7
=1+2/5
=7/5



11(x-3)=5.5*4 7.5x+30=2.5x+100
11(x-3)=5.5*4
7.5x+30=2.5x+100


1.11(x-3)=5.5*4
x-3=5.5*4/11
x=5.5*4/11+3
x=5
2.7.5x+30=2.5x+100
7.5x-2.5x=100+30
5x=130
x=26明白了麼