3 years ago

How do i do this 2y=-x+8 4x-2y+18

Mathematics

2 answers:

Arisa [49]3 years ago

6 0

Answer: x=4/31y + -18/31

Step-by-step explanation:

Let's solve for x.

2y=−x+(8)(4)x−2y+18

Step 1: Flip the equation.

31x−2y+18=2y

Step 2: Add 2y to both sides.

31x−2y+18+2y=2y+2y

31x+18=4y

Step 3: Add -18 to both sides.

31x+18+−18=4y+−18

31x=4y−18

Step 4: Divide both sides by 31.

31x/31 = 4y-18/31

Answer: x=4/31y + -18/31

lyudmila [28]3 years ago

5 0

Answer:picture

Step-by-step explanation:

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arsen [322]

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

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