Answer:
3) B 4) D
Explanation:
3) Graph the equations and locate the intersection.
4) the best method to solve number 4 is the substitution method
6x+7y=20
y=2x
we second equation is basically telling us that y=2x so we just plug it into the first equation
6x+7(2x)=20
distribute
6x+14x=20
combine like terms
20x=20
divide each side by 20
x=1
now plug in our answer into one of the equations (does not matter which one)
y=2 times 1
y=2
meaning that our answer is (1,2), x=1 y=2