Question

A is the point with coordinates (4,6)

Answer 1

Answer:

d = 9

Step-by-step explanation:

Calculate the slope of ab then equate to 3.

Calculate the slope m using the slope formula

m = $\frac{y_{2}-y_{1} }{x_{2}-x_{1} }$

with (x₁, y₁ ) = (4, 6) and (x₂, y₂ ) = (d, 21)

m = $\frac{21-6}{d-4}$ = $\frac{15}{d-4}$ = 3 ( multiply both sides by d - 4 )

3(d - 4) = 15 ( divide both sides by 3 )

d - 4 = 5 ( add 4 to both sides )

d = 9