Answer: 
Step-by-step explanation:
We know that the standard quadratic equation is ax^2+bx+c=0
Let's compare all the given equation to it and , find discriminant.
1. a=2, b= -7, c=-9
So it has 2 real number solutions.
2. a=1, b=-4, c=4

So it has only 1 real number solution.
3. a=4, b=-3, c=-1

So it has 2 real number solutions.
4. a=1, b=-2, c=-8
So it has 2 real number solutions.
5. a=3, b=5, c=3

Thus it does not has real solutions.
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>
Answer:
no because the absolute value of -7 is 7 which is greater than the absolute value of 6 which is 6.
Answer:

Step-by-step explanation:
Factorise the numerator and denominator
8a² - 2 ← factor out 2 from each term
= 2(4a² - 1) ← 4a² - 1 is a difference of squares
= 2(2a - 1)(2a + 1)
4a² + 4a + 1 ← is a perfect square
= (2a + 1)²
Thus

=
← cancel (2a + 1) on numerator/ denominator
= 
= 