25t means "25 times t" where t is some unknown number. It is a placeholder for a number.
To find what the number is, we undo what is happening to t. So we divide both sides by 25 to undo the operation "multiply by 25"
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25*t = 1125
25*t/25 = 1125/25 divide both sides by 25
t = 45
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Answer: 45
As a check, we can plug t = 45 into the equation and we should get the same value on both sides
25*t = 1125
25*45 = 1125 replace every t with 45
1125 = 1125 the answer is confirmed
