Use the substitution method to solve the system of equations. choose the correct ordered pair.
14x - 2y = 78
2x - 2y = 6
i just need to know how to do it. if you want to explain.

Ur gonna have to pick an equation and solve for a variable.

2x - 2y = 6
2x = 2y + 6 ...divide everything by 2 because u want x by itself
x = y + 3

now we sub y + 3 in for x in the other equation
14x - 2y = 78
14(y + 3) - 2y = 78...distribute thru the parenthesis
14y + 42 - 2y = 78...subtract 42 from both sides, cancelling the 42 on the left
        -42          -42

14y - 2y = 36 ...simplify
12y = 36...divide by 12 on both sides, cancelling out the 12 on the left
y = 36/12
y = 3

now , we already know that x = y + 3...and we know y = 3...so sub in 3 for y and solve for x
x = y + 3
x = 3 + 3
x = 6

solution is (6,3)

it is always a good idea to check ur answer by subbing it into one or both of the equations to see if it is correct
2x - 2y = 6(6,3)...x = 6 and y = 3
2(6) - 2(3) = 6
12 - 6 = 6
6 = 6 (correct)

so yes, ur solution is (6,3)

C. 40,320 just did the math right now