Number 18 pls help me

Mathematics

1 answer:

Harman [31]3 years ago

7 0

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

----------------------

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

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One day a store sold 36 sweatshirts. White ones cost $10.95 and yellow ones cost $11.50. In all, $404.65 worth of sweatshirts

Hatshy [7]

Answer:

17 white sweatshirts were sold and 19 yellow sweatshirts were sold.

Step-by-step explanation:

Let w represent the number of white sweatshirts sold and y represent the number of yellow sweatshirts sold.

We can write a system of equations to represent the situation.

Since the store sold a total of 36 sweatshirts, the sum of the white and yellow sweatshirts must total 36. So:

$y+w=36$

And since each white sweatshirt cost $10.95 and each yellow sweatshirt cost $11.50 and the total profit was $404.65:

$10.95w+11.5y=404.65$

Solve the system. I'll use substitution this time (though elimination will work just as perfect). From the first equation, subtract w from both sides:

$y=36-w$