Slope intercept form is y = mx + b ; m = slope.
y = -3/4x +b
If it passes through (4,7), plug those numbers in, 4 for x and 7 for y to find b (the constant)
7 = -3/4 (4) + b
7 = -3 + b Remember -3/4 * 4 = -3/4 * 4/1 (whole number converts to fraction by dividing by 1)
Add 3 to each side to get your constant "b".
b = 10
y = -3/4 x + 10
Knowing the slope intercept form is faster than figuring it out from the definition of slope. Slope requires knowing 2 points, not just one. The slope intercept form is easier to memorize and requires only two pieces of information - the slop and ONE point on the line.