Jay is incorrect in doing addition first.
Expression in maths is defined as the collection of numbers variables and functions by using signs like addition, subtraction, multiplication, and division.
Given the expression as;
3x (3 +12 divided by 3) -4.
To simplify this expression, then must follow PEMDAS.
3x(3+12÷3)
3x(3+4)
3x(7)
21x
Which means that Jay is incorrect in doing addition first.
To know more about an expression follow;
brainly.com/question/19876186
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