2x + y = 4 & x + y = 3?

Question

solve the system by substitution

Answer 1

y = 3 - x
2x + (3 - x) = 4
x + 3 = 4
x = 1
y = 2

Answer 2

1) 2x + y = 4
2) x + y = 3

Solve either equation for one of the variables and then substitute that result into the other equation.

1) 2x + y = 4
y = 4 - 2x

2) x + y = 3
x + 4 - 2x = 3
- x = - 1
x = 1

1) 2x + y = 4
2(1) + y = 4
y = 2

Check
2) x + y = 3
1 + 2 = 3
3 = 3

Lines intersect at (1, 2)

Answer 3

Hey there!

Here's the answer.

2x+y=4 --> Write the first problem.
y=4-2x --> Subtract both sides of the equation by 2x.
x+y=3 --> Write the second problem.
x+(4-2x)=3 --> Substitute 4-2x for y.
x-2x+4=3 --> Gather the x terms together and the constant terms together.
-x+4=3 --> Add x and -2x.
-x=-1 --> Subtract 4 on both sides of the equation.
x=1 --> Divide both sides of the equation by -1.
2x+y=4 --> Write the first problem.
2(1)+y=4 --> Substitute 1 for x.
2+y=4 --> Multiply 2 and 1.
y=2 Subtract both sides of the equation by 2.

So the answer is x=1 and y=2 or the solution set will be {1,2}.

Hope it helps!

Answer 4

A straightforward approach: From 2nd equation, y = 3-x. Then 1st equation becomes 2x + (3-x) = 4 or 2x - x = 4 - 3. So x = 1. Then y = 3-x = 3-1 = 2.

Answer 5

2x + y = 4
x + y = 3

Make the second equation into y= so that you can insert it into the "y" of the first equation. (substitution)

x + y = 3
y = -x + 3

Insert:

2x + (-x + 3) = 4
2x - x + 3 = 4 ----> solve for x.
x = -3 + 4
x = 1

Then put in "x" into an equation from above and solve for y.

x + y = 3
(1) + y = 3
y = 3 - 1
y = 2

Answers: x = 1, y = 2

Answer 6

Lashanda,

Take one of the two equations and solve it for either x = or y =. You may take the equation x + y = and solve for y by subtracting x from both sides, yeilding y = x - 3.

Now, take that result and wherever you see a y in the other equation, replace it with an (x - 3). You'll now have an equation in one variable that you can solve using your algebra I skills.

Good luck.

Answer 7

x=1 2x-x=x and 4-3=1 you can only do anything with the numbers with the like signs and letters with them. you'll get used to it,

5x-15/(25x-90)+(35x+45)

that's what you have to look forward to

5x-6+ 7x-3. thats the answer to it:)

Answer 8

y=-x+3
2x+(-x+3)=4
2x-x+3=4
x=1

Substitute back into the first equation:
1+y=3
y=2

Check:
2(1)+(2)=4
2+2=4

1+2=3

So x=1 and y=2

Answer 9

x+y=3
x=3-y

2(3-y) + y=4
6-2y+y=4
6-y=4
y=2*
2x+2=4
2x=2
x=1*

Answer 10

2x + y = 4
x + y = 3
---------------
I want to omit X. so, i multiply 2nd equation by (-2).

2x + y = 4
-2x - 2y = -6
-----------------
-y = -2 -----> y = 2

then: 2x + 2 = 4 ------> x = 1