Answer:

Step-by-step explanation:
The cost is given for <em>1 sweatshirt</em>. To find the cost of 15 sweatshirts, we need to multiply the expression by 15. Let's do this:

This is the expression that represents the cost of 15 sweatshirts.
Answer:
it changes by 4
Step-by-step explanation:
The quadratic formula is above.
You want each equation in standard form: ax^2 + bx + c = 0
I begin each problem by defining variables.
For instance 3. Is in standard form. X^2 -2x - 3 = 0. a = 1, b = -2, c = -3
Now use quadratic formula: x = [- b + or - sqrt(b^2 - 4ac)]\2a
If you need the y zero, you would take the 2 points on the graph of (3, 0) and (6, 0) so the 2 zero’s are 3, and 6.