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).
This line's slope is 4, then its equation should look like
y = 4x + b
We just have to find b.
Since it goes through the point (2, 5) it means that when x = 2, then y = 5. Using this information we can find b.
Step 1: replacing y = 5 and x = 2
y = 4x + b
↓
5 = 4 · 2 + b
↓ since 4 · 2 = 8
5 = 8 + b
Step 2: taking 8 to the left side of the equation
5 = 8 + b
↓
5 - 8 = b
↓ since 5 - 8 = -3
-3 = b
Then, this line's equation should have b = -3, then it is
y = 4x - 3
Answer: y = 4x - 3
