The slope or gradient of a line is a number that describes both the direction and the steepness of the line. Slope is often denoted by the letter m. In our case slope m = 3.

The equation of a line is: y = k*x + b, k is coefficient, b is the y-intercept of the line

Since y is a linear function of x , the coefficient of x is the slope of the line that is k = m . Therefore, the equation of the line is given in the form:

y = m * x + b

Since m = 3 we have y = 3*x + b

We need to find b!

Since this line y = 3*x + b is passing trough (-1, 5) if we put x = -1 and y = 5 we get:

5 = 3 * (-1) + b

b - 3 = 5

b = 5 + 3

b = 8

Finally, the equation of the line is y = 3x + 8.