What is 0.75(3.5a-6b) in distribuutive property

You multiply 0.75 into everything in the parenthesis. 0.75 * 3.5a = 2.625a and 0.75 * -6b = -4.5b. Then you would add the two answers: 2.625a + (- 4.5b ). Since there are two different variables, you cannot add the two. However, if the variables were the same, you could add them and get -1.875 (a or b).

Solve this problem with Distributive property :-
i.e a ( b+c ) = ab + bc

so, a = 0.75
b = 3.5a
and c = -6b 
And know we know that our answer will look in the form of ab + bc 

0.75 ( 3.5a - 6b ) { multipling 0.75 wth 3.5a and -6b to open phrenthsis }
= 2.625a + -4.5b { because we have + sign in our formula but our last term has negitive sign. }
= 2.625a - 4.5b { because we know that positive + negivitive is - }
we cannot solve this further because they are not like terms.
So final answer is 2.625a - 4.5b

Hope this helps..  :)

The answer is, the streetlight is 18 inches tall.