數學方程式18題(超急)要詳細計算

1.
y+7-2y=-3y+15
y-2y+3y = 15-7
2y = 8
y = 8/2
y = 4


2.
6y+4y+10=5y-5
6y+4y-5y = -5-10
5y = -15
y=-15/5
y=-3


3.
10-2y=1-y+1+7y
-2y+y-7y = 1+1-10
-8y = -8
y = (-8)/(-8)
y = 1


4.
3y-5+y=2+6y+3
3y+y-6y = 2+3+5
-2y = 10
y = 10/(-2)
y=-5


5.
8+2y+3y-5=4y-5-y
2y+3y-4y+y = -5-8+5
2y = -8
y = -8/2
y = -4


6.
5y-14+y=-3y-2-4y+1
5y+y+3y+4y = -2+1+14
13y = 13
y = 13/13
y = 1


7.
15+(3y+5)=6-(6-y)
15+3y+5 = 6-6+y
3y-y = 6-6-15-5
2y = -20
y = -20/2
y = -10


8.
3(y+1)+4(2y+2)=33
3y+3+8y+8 = 33
3y+8y = 33-3-8
11y = 22
y = 22/11
y = 2


9.
2(y-8)=4(y-5)
2y-16 = 4y-20
2y-4y = -20+16
-2y = -4
y = (-4)/(-2)
y = 2


10.
4(2y+3)-5(1-2y)=-29
8y+12-5+10y = -29
8y+10y = -29-12+5
18y = -36
y = -36/18
y = -2


11.
-8(3+4y)+2=2(5-6y)+12y
-24-32y+2 = 10-12y+12y
-32y+12y-12y = 10+24-2
-32y = 32
y = 32/(-32)
y = -1


12.
6(y+5)-8(2y-10)=-10(4y+4)
6y+30-16y+80 = -40y-40
6y-16y+40y = -40-30-80
30y = -150
y = -150/30
y = -5


13.
x/2 +x=3
(x/2)*2 + 2x = 3*2
x+2x = 6
3x = 6
x = 6/3
x = 2


14.
x/2-x/3=1
(x/2)*6 - (x/3)*6 = 1*6
3x-2x = 6
x = 6


15.
2x/5+x/2=9
(2x/5)*10 + (x/2)*10 = 9*10
4x+5x = 90
9x = 90
x = 90/9
x = 10


16.
y/2=1- 3y/4
(y/2)*4 = (1-3y)/4*4
2y = 1-3y
2y+3y = 1
5y = 1
y = 1/5


17.
y-4=y+16/3
(y-4)*3 = (y+16)/3*3
3y-12 = y+16
3y-y = 16+12
2y = 28
y = 28/2
y = 14


18.
10+y/2=8-2y/3
(10+y)/2*6 = (8-2y)/3*6
3(10+y) = 2(8-2y)
30+3y = 16-4y
3y+4y = 16-30
7y = -14
y = -14/7
y = -2