Line equation
We know that the equation of a line is given by
y = mx + b, where m and b are numbers: m is its slope (shows its inclination) and b is its y-intercept.
We want to find m and b in order to write the equation.
We know that m = 4, then
y = mx + b
↓
y = 4x + b
Now we need to find b. We do it just by replacing by the given point (2, -3) where x = 2 and y = -3:
y = 4x + b
↓
-3 = 4 · 2 + b
-3 = 8 + b
↓ Substracting 8 both sides
-8 - 3 = b
-11 = b
Now, we have the complete equation:
y = 4x -11