Answer:
see below
Step-by-step explanation:
slope = (y₂ - y₁) / (x₂ - x₁) <=== formula
= (2 - (-7)) / (18 - 18)
= 9 / 0
= 0 <=== slope
2.57 x 10^1
is the scientific notation of 25.7
Answer: You can simply use a calculator.