y = mx + b
First equation 1 = m(4) + b, bring everything to one side m(4) + b - 1 = 0
Second equation 7 = m(5) + b, bring everything to one side m(5) + b - 7 = 0
Set them equal to each other,
m(4) + b - 1 = m(5) + b - 7
If you bring the b over to the left hand side it becomes
m(4) + b - b - 1 = m(5) - 7
m(4) - 1 = m(5) - 7
Solve for m
6 = m
Plug m = 6 into either equation from the beginning,
m(4) + b - 1 = 0
6(4) + b - 1 = 0
24 + b - 1 = 0
b = -23
Knowing m and b we can now make an equation
y = mx + b
y = 6x -23 Final answer