How many solutions does the system of equations have?

y = −2x +12
4y + x −20 = 0

3 answers

To solve this system of equations, we can use substitution. We know that y in the second equation is equal to -2x + 12 based on the first equation, so we can substitute that into the second equation:

4(-2x + 12) + x - 20 = 0

Simplifying this equation, we get:

-8x + 48 + x - 20 = 0
-7x + 28 = 0
-7x = -28
x = 4

Now that we know x is 4, we can substitute that back into either equation to solve for y. Let's use the first equation:

y = -2(4) + 12
y = 4

So the solution to this system of equations is (4, 4). Therefore, there is only one solution.
all you need to know is that the slopes are different.
Therefore the lines will intersect in a point -- the solution.
Yes, that is correct. If the slopes of two lines are different, then the lines intersect at exactly one point, giving us a unique solution for the system of equations.