how do you solve for x if y=3x+4?

y=3x+4
3x+4=y
3x=y-4
x=y-4/3

2006-09-23 19:00:00 · answer #1 · answered by winniesoh2002 1 · 0⤊ 0⤋

You want to isolate x. Islate is just a fancy word for get x on one side of the equal sign and put everything else on the other side of the equal sign.

There is a rule in math, that whatever you do to one side of the equation you have to do to the other side. So if, for example, you subtract 10 from one side, then you must subtract 10 from the other side

Ex: 10 = 10
Subtract 10
10-10 = 10 - 10
0 = 0

Also you can divide or multiply both sides of the equation by the same thing.

In y = 3x + 4, you want to move the 4 to the other side of the equation. To do so, simply subtract 4 from both sides

y = 3x + 4
y-4 = 3x+4 - 4
y-4 = 3x

Now you want to make the 3x into x. To do so, simply divide by 3.

y-4 = 3x
(y-4)/3 = (3x)/3

The 3's on the right side cancel out, leaving you with:
(y-4)/3 = x

x = (y-4)/3

2006-09-23 18:57:56 · answer #2 · answered by Manan T 3 · 0⤊ 0⤋

x = y+4/3

2006-09-23 18:47:24 · answer #3 · answered by martin h 6 · 0⤊ 2⤋

To manipulate an equation what you need to know is that when you move from one side of the equation to the other the operator becomes the opposite : so if it's plus on one side it will become minus on the other ; if it's a multiplier it becomes a divider.

Your equation y=3x+4 is actually y = 3 multiply x plus 4

transferring one at a time

the plus 4 will become minus 4

y minus 4 = 3 multiply x

the 3 multply will become divide by 3

y minus 4 divided by 3 = x

transferred back to mathematical

(y-4) / 3 = x

2006-09-23 19:09:57 · answer #4 · answered by enirgo 2 · 0⤊ 0⤋

step 1: subtract 4 from both sides to get

y-4=3x+4-4 which equals y-4=3x

step 2: divide both sides by 3 to get

(y-4)/3=3x/3 which equals (y-4)/3=x

2006-09-23 18:56:36 · answer #5 · answered by RLP 3 · 0⤊ 0⤋

y=3x+4
=>x=(y-4)/3
The value of y must have been given. So you can solve for x. But to solve for 2 variables, you need atleast 2 equations.

2006-09-23 18:49:34 · answer #6 · answered by Anonymous · 0⤊ 0⤋

accorging to the value of y the value of x changes
for eg: if y=-2,then
-2=3x+4
-2-4=3x
-6=3x
so,x=-2

2006-09-23 19:02:17 · answer #7 · answered by HEMNATH 2 · 0⤊ 0⤋

y=3x+4(subtract 4 on both sides)
y-4=3x(divide both sides by 3)
y-4/3=x

2006-09-23 18:49:52 · answer #8 · answered by smit j 1 · 0⤊ 0⤋

subtract 4 from both sides
y-4=3x+4-4

y-4=3x

Divide each side by tree
x=(y-4)/3

2006-09-23 20:08:29 · answer #9 · answered by iyiogrenci 6 · 0⤊ 0⤋

if you are solving for a variable you want to get that variable alone so first you would subtract 4 from both sides

y-4=3x

then divide by 3

(y-4)/3 = x

that is your answer

2006-09-23 18:47:29 · answer #10 · answered by DE 2 · 0⤊ 0⤋

I'm doing this sort of thing. you can make y=0 then solve it. Also can change the subject of the equation like
3x+4=y
3x=y-4
x=y-4/3
Which do you need?

2006-09-23 19:45:06 · answer #11 · answered by Fenrispro 3 · 0⤊ 0⤋

how do you solve for x if y=3x+4?

14 answers