Pearson Algebra 1 Common Core, 2011
PA
Pearson Algebra 1 Common Core, 2011 View details
Cumulative Standards Review

Exercise 2 Page 658

Substitute each ordered pair into the inequality and check whether it results in a true statement.

I

Practice makes perfect
We are given an inequality.

3x-y<20 There are four options, each with an ordered pair. We will find which one of these ordered pairs satisfies the inequality. To do so, we will substitute each point into the inequality and check whether it results in a true statement.

Option Ordered Pair Substitution Statement
F ( 7, 1) 3( 7)- 1? <20 20≮ 20 *
G ( 5, - 6) 3( 5)-( - 6)? <20 21≮ 20 *
H ( 8, 0) 3( 8)- 0? <20 24≮ 20 *
I ( - 1, - 4) 3( - 1)-( - 4)? <20 1<20 âś“
To see a step-by-step explanation for these calculations, please see the bottom of this solution. As we can see from the table, the ordered pair (- 1,- 4) makes our inequality true. It means that this ordered pair is a solution to our inequality, which corresponds to option I.

Showing Our Work

Substitution of Ordered Pairs in an Inequality
Let's explain the calculations in the substitutions step-by-step. We will start with the point (7,1) and substitute x=7 and y=1 into the inequality.
3x-y<20
3( 7)- 1? <20
21-1? <20
20≮ 20 *
As we can see, the point (7,1) does not make our inequality true. Now, let's substitute the point (5,- 6) into the inequality.
3x-y<20
3( 5)-( - 6)? <20
15-(- 6)? <20
15+6 ? <20
21≮ 20 *
We can see that the point (5,- 6) does not make our inequality true. We will now substitute the point (8,0) into the inequality.
3x-y<20
3( 8)- 0? <20
24-0? <20
24≮ 20 *
The point (8,0) also does not make our inequality true. Finally, let's substitute the point (- 1,- 4) into the inequality.
3x-y<20
3( - 1)-( - 4)? <20
- 3-(- 4)? <20
- 3+4? <20
1<20 âś“
As we can see, the point (- 1, - 4) makes our inequality true.