Question

In the standard (x, y) coordinate plane, what is the slope of the line joining the points (3,7) and (4,−8)?

Answer 1

$(3,7) \ and \ (4,-8)\\ \\ First \ find \ the \ slope \ of \ the \ line \ thru \ the \ points \: \\ \\ m= \frac{y_{2}-y_{1}}{x_{2}-x_{1} } \\ \\m=\frac{-8-7}{4-3} = \frac{-15}{1}=-15 \\ \\Now \ use \ y = mx + b \ with \ either \ point \ to \ find \ b, \ the \ y-intercept \ : \\ \\ y=mx+b \\ \\7=-15*3+b\\ \\7=-45 +b \\ \\b=7+45\\ \\b=52 \\ \\ y= - 5x+52 \ is \ the \ answer$