The formula for the equation describing a straight line is y = b0 + b1x. the value for b1 in this equation represents the

Equation of a straight line is normally in the form: y = mx + c.

Where, m and c are constants in which;
m = gradient
c = y-intercept.

Comparing this standard way way of writing the equation of a straight line with the current scenario, this equation can be rewritten as;
y = b1x + b0.

This way, b1 = gradient of the line while b0 = y-intercept.