First thing you want to do, is reverse the question.
57/3 - 3.
57/3 = 19.
19 - 3.
Your answer is 16.
Answer:
The leghts of AB is 9 because both of the triangles are symmetrical. But also, this is a Equilateral triangle, which means that both of the sides are the same lengths (AB=AC)
ANSWER

EXPLANATION
The given expression is

We regroup the numerical parts to get;

Now let us simplify the negative numbers.

We now subtract 19 from 42 to get;

We can't simplify further
Hence the simplest form is:

If you write a number over another number, it's called a FRACTION
Answer:
75 ft
Step-by-step explanation:
Let 20/50 = 30/x
So,
20X = 30x50
20x = 1500
X = 1500/20
X = 75
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