(Plug-in & PEMDAS)
Step 1. Substitute the given values for the variables in for letters in the given expression. Be sure to use parentheses where appropriate. Avoid using the dot or an x for for multiplication when you do this.
Step 2. Simplify the expression using PEMDAS.
Directions: Please evaluate the given expression for the given values of the variables.
-2(x+y)+4x-3y+9xy x=-5 & y=10
| Step 1. Plug-in |
-2(-5+10)+4(-5)-3(10)+9(-5)(10) |
| Step 2. PEMDAS |
-2(5)+4(-5)-3(10)+9(-5)(10) -10-20-30-450 -30-30-450 -60-450 -510 |
Directions: Please evaluate the given expressions for the the given values of the variables.

Directions: Please write 1-2 paragraphs that thoroughly address the following.
1. Why is it important to use parentheses appropriately when you are plugging in values into an expression for evaluation? Please give examples that support your answer.
2. What is the importance of trying to write the answers to these types of problems in a line by line fashion?