[tex]3(2(2) + 3) = 21[/tex]
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Use PEMDAS:
P Parentheses first
E Exponents (ie Powers and Square Roots, etc.)
MD Multiplication and Division (left-to-right)
AS Addition and Subtraction (left-to-right).
[tex]3(2(2)+3)=3(4+3)=3(7)=21[/tex]