Answer :
well, you would istribute
using
a(b+c)=ab+ac
so
3(g+5)=3(g)+3(5)=3g+15
2(3g-6)=2(3g)+2(-6)=6g-12
now we gots
3g+15+6g-12
using commutative, we can arrange and group like terms because
a+b=b+a
so
3g+6g+15-12
add
9g+3
using
a(b+c)=ab+ac
so
3(g+5)=3(g)+3(5)=3g+15
2(3g-6)=2(3g)+2(-6)=6g-12
now we gots
3g+15+6g-12
using commutative, we can arrange and group like terms because
a+b=b+a
so
3g+6g+15-12
add
9g+3