1.( 2x ) ( 10x ) = 20 x²
2. -3m( m + 8 ) = -3m² - 24m
3. 4d( 2d -9 ) = 8d² - 36d
4. ( 3x + 4 ) ( x -2 ) = 3x² - 6x + 4x - 8 = 3x² - 2x -8
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5. ( 2y -1 ) ( 4y - 3 ) = 8y</span>² - 6y - 4y + 3 = 8y² -10y +3
5.
Let x be the age of the father and y be the age of the son. As of today, he's 3 times older, so we have 
10 years ago their ages were, respectively, x-10 and y-10, and the father was 5 times older: 
So, we have the system

Using the first equation, we can substitute every occurrence of "x" with "3y" in the second equation:

So, the son is 20 years old, which means that the father is 60 years old.
Indeed, 10 years ago they were 10 and 50 years old, so the father was 5 times older.
6.
Let x be the age of the grandfather and y the age of the granddaughter. We know that the grandfather is 10 times older: 
He also is 54 years older: 
Again, if we substitute x=10y in the second equation we have

Answer: FALSE
Step-by-step explanation:
An Irrational number is a decimal t hat is non repeating while a rational number is s repeating decimal.
Answer:
add the numbers and divide by how many numbers there are, thats how you find the mean
Step-by-step explanation:
Answer:
D
Step-by-step explanation: