y=x+4 and y=-3x-3?

Question

how do you solve this? What solution is it???

Answer 1

Subtract the second equation from the first equation:

y - y = (x + 4) - (-3x - 3)
0 = 4x + 7
4x = -7
x = -7/4

Now plug this back into the first equation:
y = (-7/4) + 4 = (-7/4) + (16/4) = 9/4

So the solution is:
(x, y) = (-7/4, 9/4)

Answer 2

We have a system of equations
(1) : y = x + 4
(2) : y = -3x - 3

Multiply (1) by 3, we get
3y = 3x + 12
Then add (1) and (2)
3y = 3x + 12
y = -3x - 3

3y + y = 12 - 3
4y = 9
y = 9/4
Then substitute to find x
9/4 = x + 4 ==> x = 9/4 - 4 = 9/4 - 16/4 = -7/4

Answer 3

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

since y = y we can set the 2 equations to equal each other
x+4 = -3x - 3
x + 3x = -3 -4
4x = -7
x = -7/4
Now solve for y knowing x, pick the easiest equation t work with, that would be the first:
y=x+4
y = -7/4 + 4
multiply the whole equation by 4 to get:
4y = -7 + 16
4y = 9
y = 9/4

Answer 4

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

Solution (find x):
x + 4 = - 3x - 3
4x = - 7
x = - 7/4 or - 1 3/4

Find y (plug value of x):
y = - 1 3/4 + 4
y = 2 1/4

Answer: x = - 1 3/4, y = 2 1/4

Proof:
2 1/4 = - 1 3/4 + 4
2 1/4 = 2 1/4

2 1/4 = - 3(- 1 3/4) - 3
2 1/4 = 5 1/4 - 3
2 1/4 = 2 1/4

Answer 5

As they are already in value of Y, we can just igualate one with the other

x + 4 = -3 x - 3

4 x = - 7

x= - 7/4

Now with this result we go to one of the equations and find the value of y

y= - 7/4 + 4

y= 9 / 4

Answer 6

y=x+4
y=-3x-3
x+4=-3x-3
4x=-7
x=-7/4
y=-7/4+4=9/4