−3(2x+7)

−6x−21

To simplify the expression −3(2x+7), you can apply the distributive property:

−3(2x+7) = −3*2x + (−3)*7

Now, you can simplify each term in the expression:

−3*2x = −6x
(−3)*7 = −21

Combining the simplified terms, the expression becomes:

−6x − 21