When applying indirect proofs, we assume the negation of the conclusion is true, and show that this assumption would lead to nonsense, or contradiction.
In our case we assume a is not smaller than 7, that is we assume a≥7.
a≥7 then, multiplying both sides by 3:
3a≥21, then, adding both sides 7:
3a+7≥28,
which is a contradiction because 3a+7 is smaller than 28.
So our assumption is wrong, which means the opposite of it is correct.
Answer: assume a≥7
Answer:
866
Step-by-step explanation:
She could add the hundreds first: 400+400=800
Then the tens: 50+10=60
Then the ones: 0+6=6
And add them all up: 800+60+6=866
<h3>
Answer:</h3>
<h3>
Step-by-step explanation:</h3>
We can let the variables A and B stand for the length in inches of fish A and fish B, respectively.
If we assume each person bought fish having a total length of 1 inch per gallon of aquarium, then we can write equations ...
... 3A +2B = 33 . . . . . total length of Marta's fish
... 3A +4B = 45 . . . . . total length of Hank's fish
Subtracting the first equation from the second, we get ...
... 2B = 12
... B = 6 . . . . . divide by 2
Using this value in the first equation, we have ...
... 3A + 2·6 = 33
... 3A = 21 . . . . . . . . subtract 12
... A = 7 . . . . . . . . . . divide by 3
Fish A is 7 inches long; fish B is 6 inches long.
T=65$+(65$*.06)
T=65$+3.9$
T=68.9$
