Answer:
2/3
Step-by-step explanation:
42/63 = 2/3
15/22.5 = 2/3
1) Final expression: 
2) Final expression: 
Step-by-step explanation:
1)
The first expression is

First, we remove the 2nd bracket by changing the sign of all the terms inside:

Now we group the terms with same degree together:

Now we solve the expression in each brackets:

So, this is the final expression.
2)
The second expression is

We apply the distributive property, so we rewrite the expression as follows:

Solving both brackets,

Now we group terms of same degree together:

And solving each bracket,

So, this is the final expression.
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Answer:
9
Step-by-step explanation:
n(A)+n(B) [n(A)=cardinal numbers of set A.so we have to count the elements and write .
=4+5
=9
Answer:
The length is 99 cm
Step-by-step explanation:
The perimeter of a rectangle is
P = 2 (l+w)
310 = 2( l+56)
Divide each side by 2
310/2 = 2/2( l+56)
155 = l+56
Subtract 56
155-56 = l+56-56
99 = l
Isolate the variable by dividing each side by factors that don't contain the variable.
x = −1