5(x+8)-5=-6(2x-7)

5(x+8)-5=-6(2x-7)


5(x+8)-5=-6(2x-7),去括弧
5x+40-5=-12x+42,移項
5x+12x=42-40+5,合併
17x=7,係數化1
x=7/17



1/9{1/7[1/5(x-1)+6]+8}=1
為什麼我算不出來啊


1/9{1/7[1/5(x-1)+6]+8}=1
1/7[1/5(x-1)+6]+8=9
1/7[1/5(x-1)+6]=1
1/5(x-1)+6=7
1/5(x-1)=1
x-1=5
x=6



7:x=2.8:5.6


7/2.8×5.6=14



解方程:2.1÷x=0.3,7.2-x=4.3,x-0.84x=0.8,30×(x÷4)=60,84+x=10.2


2.1÷x=0.3
x=2.1÷0.3
x=7
7.2-x=4.3
x=7.2-4.3
x=2.9
x-0.84x=0.8
0.16x=0.8
x=5
30×(x÷4)=60
x÷4 =60÷30
x÷4 =2
x =4×2
x =8
84+x=10.2
x=10.2-84
x= -73.8