Answer
The most efficient method to solve this system is substitution because we can easily substitute the value of y, given by the second equation, into the first equation .
The solution is: (-3,-2)
Work Step by Step
Our two systems are:
1. 2x+7y=-20
2. y=3x+7
Lets substitute the second equation into the first equation for y.
2x+7(3x+7)=-20. (Distribute the 7)
2x+21x+49=-20. (Simplify)
23x+49=-20 (Subtract 49 from both sides)
23x=-69. (Divide by 23 on both sides)
x=-3
Now that we know the value of x, lets substitute it into the second equation to find the value of y.
y=3(-3)+7. (Simplify)
y=-2
So by using substitution, we got our answer to be: (-3,-2)
