CPM Homework Help : CCA2 Problem 1-25

Note: The stoplight icon to the right of a problem indicates that there is an error in the problem.

Find the error in the solution at right. Explain what the error is and solve the equation correctly. Show how to check your solution to be sure that it is correct.

$3(x−2)−2(x+7)=$ $2x+17$

$\\ 3x − 6 − 2x + 14 =$ $2x + 17$

$\\x + 8 = 2x + 17$

$\\-9=x$

Hint:

Notice that the binomial $(x+7)$ is being multiplied by $−2$ .

More Help:

Use the Distributive Property correctly and continue solving.

Answer:

The error is in line 2.
It should be $−14\ \text{not}\ +14$ .
$3x−6−2x−14=2x+17$
Continue solving to get $x=−37$ .

Checking:

Substitute $−37$ for $x$ in the original equation and simplify both sides to compare results.
Result should be $−57=−57$ .