Answer:
5/9
Step-by-step explanation:
Answer: 
Step-by-step explanation:
For this exercise you need to remember:
1) The mulitplication of signs:

2) By definition, like terms contain the same variables with the same exponent.
Then knowing this, and given the equations:
and 
You must subtract the like terms, which means that you must subtract the numerical coefficients of each term.
Then, you get the result is:

Answer:
see below
Step-by-step explanation:
butterfly = x minutes
breast = y minutes
total is 50 minutes
breast stroke = butterfly +20
Part A
x+y = 50
y = x+20
Part B
Substitute the second equation into the first
x+ (x+20) = 50
2x+20 = 50
2x+20-20 = 50-20
2x = 30
2x/2 = 30/2
x = 15
y = x+20
y = 20+15
y = 35 minutes
35 minutes on the breast stroke
Part C
45 minutes on the butterfly is not reasonable
We only have a total of 50 minutes
50-45 = 5
But he spend more time on the breast stroke ( 20 minutes more), but if he spend 45 minutes on the butterfly, he would have to spend less on the breast stroke.
Answer:
A,CAND D
Step-by-step explanation:
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