Answers − Solving Equations, Addition and Subtraction 1
1. If 20 + y = 42, solve y
The inverse of 20 is − 20. So subtract 20 from both sides
To verify, put the value of y = 22 back into the original equation
20 + 22 = 42
2. If 6 + z = 15, solve z
The inverse of 6 is − 6. So subtract 6 from both sides
To check, put the value of z = 9 back into the original equation
6 + 9 = 15
3. If 7 + t = 35, what is value of t?
The inverse of 7 is − 7. So subtract 7 from both sides
To verify, put the value of t = 28 back into the original equation
7 + 28 = 35
4. If 9 + z = 7, solve z
The inverse of 9 is − 9. So subtract 9 from both sides
To check, put the value of z = −2 back into the original equation
9 + (−2) = 9 − 2 = 7
5. If x − 15 = 7, what is value of x?
The inverse of − 15 is + 15. So add 15 to both sides
To verify, put the value of x = 22 back into the original equation
22 − 15 = 7
6. If y − 120 = 4, solve y
The inverse of − 120 is + 120. So add 120 to both sides
To check, put the value of y = 120 back into the original equation
124 − 120 = 4
7. If z − 10 = −5, what is value of z?
The inverse of − 10 is + 10. So add 10 to both sides
To verify, put the value of z = 5 back into the original equation
5 − 10 = −5
8. If a − 25 = −38, solve a
The inverse of − 25 is + 25. So add 25 to both sides
To check, put the value of a = −13 back into the original equation
−13 − 25 = −38
9. If 17 + b = −5, what is value of b?
The inverse of 17 is − 17. So subtract 17 from both sides
To verify, put the value of b = − 22 back into the original equation
17 + ( − 22 ) = 17 − 22 = −5
10. If c + 20 = −34, solve c
The inverse of 20 is − 20. So subtract 20 from both sides
To check, put the value of c = −54 back into the original equation
−54 + 20 = −34
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