Answer:
a = - 1
Step-by-step explanation:
Calculate the slope m using the gradient formula
m = ( y₂ - y₁ ) / ( x₂ - x₁ )
with (x₁, y₁ ) = (- 2, 7) and (x₂, y₂ ) = (a, 2)
m = [tex]\frac{2-7}{a+2}[/tex] = [tex]\frac{-5}{a+2}[/tex] = - 5
multiply both sides by (a + 2)
- 5 = - 5(a + 2) ( divide both sides by - 5 )
1 = a + 2 ⇒ a = 1 - 2 = - 1
