I think it might be 90 degrees
- Slope formula:

Firstly, let's set up our equation. Place the two coordinates in the slope formula and have it equal 8: 
Next, combine like terms: 
Next, multiply both sides by 7: 
Next, add 4 onto both sides of the equation: 
Lastly, divide both sides by 2 and <u>your answer will be
</u>
Answer:
21,7 - yes
28,3 - no
17,3 - no
20,4 - yes
55,5 - yes
15,5 - yes
26,4 - no
32,8 - yes
48,7 no
60,2 - yes
79,4 - no
81,3 - yes
Step-by-step explanation:
hope that helps
Answer:
Step-by-step explanation:
7) 2ab + 4ac = 2*a*b + 2 *2 *a*c
= 2a(b + 2c)

8) ac - a²c² = c( a - a²c)
bc - abc = c(b - ab)


9) b²+ 4b - 5 = b² + 5b - 1b - 5
= b(b + 5) - 1(b + 5)
= (b +5)(b - 1)
b² + 8b + 15 = b² + 5b + 3b + 15
= b(b + 5) + 3(b + 5)
= (b + 5 )(b + 3)

