Pearson Algebra 1 Common Core, 2011
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Pearson Algebra 1 Common Core, 2011 View details
8. An Introduction to Equations
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Exercise 64 Page 57

Substitute the given values into the expression to create the table. Analyze the pattern carefully to get the conclusions.

Evaluation: See solution.
Pattern: Each value of x is doubled and then increased by 2.
Solution: 13

Practice makes perfect
We are given the expression, and we want to evaluate it for different values of x and analyze the emerging pattern. 2x + 2 Let's start by substituting the first value x=- 2 into the expression and simplifying following the order of operations.
2x + 2
2( -2) +2
-4 + 2
- 2
For the value x=- 2 our expression simplifies to - 2. We can do the same for other values as well. For this we will use a table to organize our information.
x 2x+2 Result
-2 2( -2) +2 - 2
-1 2( -1) +2 0
0 2( 0) +2 2
1 2( 1) +2 4
2 2( 2) +2 6
3 2( 3) +2 8
Notice that for each result, the value increases by 2. We will use this conclusion to solve the equation 2x+2=28. Since x=-1 gives us a result of 0, we can calculate how many times we would need to increase x before the result gives 28. 28Ă· 2= 14 times We would need to increase x 14 times. This means that the value for x that will solve the equation is -1+ 14=13. Let's check our theory by substituting 13 into the given equation and simplifying.
2x+2=28
2* 13+2? =28
26+2? =28
28=28
Because the left-hand side and right-hand side match, we know that our solution is correct.