The correct answer is: <span>D. The regression line is not a good model because the points in the residual plot form a curve. (i know this because i just passed the test ;) )</span>
He had saved 320 initially
Step-by-step explanation:
Let the amount he saved be 'a'
Amount spent = 20 + 40 + 30
= 90
His grand father gave 50
At the end he has 280
280 = a - 90 +50
a = 280 -50 +90
= 320
He had saved 320 initially
88 degrees is the correct answer
On solving the linear system, for the value of y = 15, the value of x is 200. The correct option is D.
<h3>What is the linear system?</h3>
It is a system of an equation in which the highest power of the variable is always 1. A one-dimension figure that has no width. It is a combination of infinite points side by side.
Given
The linear equation is shown below.

The equation can be written as

For y = 15, the value of x will be.

The value of x is 200.
Thus, option D is correct.
More about the linear system link is given below.
brainly.com/question/20379472