9 + 3 × 2² - 1 × 4
= 9 + 3 × 4 - 1 × 4
= 9 + 12 - 1 × 4
= 21 - 1 × 4
= 21 - 4
= 17
Follow the order of PEMDAS, where,
P = Parentheses
E = Exponents
M = Multiplication
D = Division
A = Addition
S = Subtraction
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Hope it helps ⚜