Answer:
12) x= 21
13) x = 1
14) x = 9
15) x = 1
Explanation:
Here, we are being asked to solve the given equations and check our work.
To check the work, we need to substitute the found value of x into the equation to check if it makes a true and correct statement.
12) Solve for x:
Check your work:
13) Solve for x:
Check your work:
14) Solve for x:
Check your work:
15) Solve for x:
Check your work: