3 years ago

A principal was buying T-shirts for his school's chess club and found that the total cost

Mathematics

1 answer:

GaryK [48]3 years ago

6 0

I think the answer is C

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Help. Look at image. I don't get this.

Nadusha1986 [10]

Answer:

she spent 91.18 dollrs

Step-by-step explanation:

simply add the blouse shoes and shirt prices,

times .20, subtract frmo total

6 0

2 years ago

Read 2 more answers

Please teach me on how to answer this question. (addmath question)

arsen [322]

We know that $\overline{x}=8$ so:

$\overline{x}=8\\\\\\\dfrac{\sum\limits_{k=1}^7\,x_k}{7}=8\qquad|\cdot7\\\\\\ \boxed{\sum\limits_{k=1}^7\,x_k=56}$

We want to calculate:

$\sum\limits_{k=1}^7\,\big(2x_k-3\big)^2=\sum\limits_{k=1}^7\,\big(4x_k^2-12x_k+9\big)=\\\\\\=\sum\limits_{k=1}^7\,4x_k^2-\sum\limits_{k=1}^7\,\big12x_k+\sum\limits_{k=1}^7\,9=4\sum\limits_{k=1}^7\,x_k^2-12\sum\limits_{k=1}^7\,x_k+\sum\limits_{k=1}^7\,9=\\\\\\=4\cdot672-12\cdot56+7\cdot9=2688-672+63=\boxed{2079}$