Lila did it correctly. The answer is 324
Following PEMDAS, we first focus on the parenthesis. So we simplify 9-3 to get 6
So we go from
18*4^2+(9-3)^2
to
18*4^2+6^2
The next step is applying exponents. In this case, squaring the terms, so we go from
18*4^2+6^2
to
18*16+36
Next is multiplying
18*16+36
turns into
288+36
Finally, add up 288 and 36 to get 288+36 = 324
That confirms that Lila is correct
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The error that Rob made is that he computed 18*4^2+9^2-3^2 but it is NOT correct. Saying (x-y)^2 = x^2-y^2 isn't a true equation for all x and y. Again you have to simplify what is in the parenthesis first, and then you can square it. Or you must use the FOIL rule to expand out (9-3)^2
Using the calculator it is 27.47 round off to 27.5
2y+3x-5x^2-g contains 4 terms that cannot be further simplified without know the values for the variables y, x, and g. Although 3x and -5x^2 contain the same variable x, since they have have different exponents, we can not directly add them together without knowing the value of x.
The answer is 4.
