18) 3(3x - y) = 9x - y is the question
Distribute 3 to all terms within the parenthesis (3x and -y). Remember to bring the sign.
3(3x) = 9x
3(-y) = -3y
9x - 3y ≠ 9x - y
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19) Write the missing numbers in the pattern below:
7, __, 21, __, 35, 42
From what we can see of the numbers next to each other (35 & 42), subtract the two numbers
42 - 35 = 7.
As you can see, the number is 7. Subtract 7 from 35
35 - 7 = 28
Subtract 7 from 28
28 - 7 = 21
Subtract 7 from 21
21 - 7 = 14
you're two answers are bolded & underlined: 7, 14, 21, 28, 35, 42
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hope this helps