Answer:
This is what you have to explain:
With 5n, you are multiplying a number and a variable.
With 5 + n, you are adding a number and a variable.
Answer:
The coordinates of D is (-4,-9)
Step-by-step explanation:
Given
C = (2,7)
<em>M=(-1,-1) ----- Missing part of question</em>
Required
Determine the coordinates of D
<em>Let the coordinates of D be (x₂,y₂)</em>
<em>We'll solve this question using mid point formula;</em>
<em></em>
<em></em>
<em>Where</em>
and 
Put these values in the formula

By comparison;
and 

Multiply both sides by 2

Subtract 2 from both sides



Multiply both sides by 2

Subtract 7 from both sides


<em>Hence, the coordinates of D is (-4,-9)</em>
9 dollars represents 90% of the cost. Divide 9 by 0.90 to get the original price, 10 dollars