Use PEMDAS, which stands for Parenthesis, Exponents, Multiply, Divide, Add, and Subtract.
First multiply, so 86 x 450 = 38700, and then divide 47 divided by 10, which is 4.7, and then add 4.7 plus 38700, which would give you 38704.7
3s is 3 times sydneys age. so the equation would be 3s-5
The answer would be 3 cups of juice
