The value of expression is 7.
<h3>What is expression?</h3>
An expression is a combination of numbers, variables, functions (such as addition, subtraction, multiplication or division etc.)
Given:

Now, using property of log
a log b
So,
= 7 log 10
As log 10 = 1
= 7 (1)
= 7
Learn more expression here:
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The square root of 225 is 15 :)
Answer:
y = 2
Step-by-step explanation:
20y - 21 = 10y - 1
20y = 10y + 20
10y = 20
y = 2
640. the answer would be 640