I need help
McKenna was asked to write the following expression in standard form.

3−5(3a+6)
When writing the expression in standard form, McKenna made a mistake.
3−5(3a+6)3+(−5)(3a+6)−2(3a+6)−6a+(− 12)−6a−12 Step 1 Step 2 Step 3 Step 4
a. McKenna made her first mistake in
.
b. The correct expression in standard form is
.