Using substitution, which number from the set {6, 13, 18, 26} makes the equation 2x+5=31 true?
Responses
18
26
6
13
First we substitute 18 into the equation:
2(18) + 5 = 31
36 + 5 = 31
41 = 31
This is not true, so we eliminate 18 from the set.
Next, we substitute 26 into the equation:
2(26) + 5 = 31
52 + 5 = 31
57 = 31
This is also not true, so we eliminate 26 from the set.
Then we substitute 6 into the equation:
2(6) + 5 = 31
12 + 5 = 31
17 = 31
This is also not true, so we eliminate 6 from the set.
Finally, we substitute 13 into the equation:
2(13) + 5 = 31
26 + 5 = 31
31 = 31
This is true, so the answer is 13.