4X+9=209怎么解?4X+9=209 X-128=320 81-X=23 5X-7X=144 这4个方程怎么截?

(1)=50
(2)=448
(3)=104
(4)=-72

4x+9=209
4x=209-9
4x=200
x=50
x-128=320
x=320+128
x=448
81-x=23
-x=23-81
-x=-58
x=58
5x-7x=144
2x=144
x=72
移项的时候要变号 负负得正 不懂的话好好问你的数学老师
小朋友，要好好学习哈，这些题目难不倒你的
记得以后自己动脑筋

4X+9=209 -> 4X+9-9=209-9 -> 4X=200 X-128=320 X=50
X-128=320 -> X-128+128=320+128 -> X=448
81-X=23 -> 81-X+X=23+X -> 81=X+23 -> 81-23=X+23-23 ->X=58
5X-7X=144 -> X(5-7)=144 -> -2X=144 -> 2X=-144 -> X=-72

4X=209-9=200,X=50
X=320+128=448
X=81-23=58
-2X=144,2X=-144,X=-72

4X+9=209
4X=200
X=50
----------
X-128=320
X=128+320
X=448
81-X=23
X=81-23
X=58
5X-7X=144
-2X=144
X=-72

4X+9=209
X=(209-9)除以4
X=50
X-128=320
X=320+128
X=448
81-X=23
X=81-23
X=58
5X-7X=144
-2X=144
X=144除以-2
X=-72

(1)=50
(2)=448
(3)=104
(4)=-72