The length of model is ......15 inch
if the scale factor is 1/20
it means 1/20=15/h
h=12*15=300
So you need to use the distributive property. First, solve inside the parentheses. So, 8x times 4y is 32xy, then multiply that by 3 to get 96xy, now multiply 96xy by 2 to get your final answer of 192xy.
3÷8+1÷8-(9÷8+5÷8)
=3÷8+1÷8-(14÷8)
=3÷8+1÷8-14÷8
=(3+1-14)÷8
=-10÷8
=-5÷4
=-1.25