How do you solve $2 x + 7 y = 30$ $2x + 7y = 30$ and $x = 48 - 9 y$ $x = 48 - 9y$ using substitution?

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How do you solve $2 x + 7 y = 30$ $2x + 7y = 30$ and $x = 48 - 9 y$ $x = 48 - 9y$ using substitution?

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Answer 1 · 2016-05-11T21:08:18

$y = 6$ $y = 6$

Explanation:

$2 x + 7 y = 30 and x = 48 - 9 y$ $2x + 7y = 30 " " and " " color(red)(x = 48 - 9y)$

Remember that the = sign tells us that two expressions are absolutely the same as each other - specifically that they are inter-changeable! In these equations: $x IS THE SAME AS (48 - 9y)$ $"x IS THE SAME AS (48 - 9y)"$ .

So, in the first equation an $x$ $x$ can be replaced by (48 - 9y).

$2 x + 7 y = 30 \Rightarrow 2 (48 - 9 y) + 7 y = 30$ $2color(red)x + 7y = 30 " " rArr 2color(red)((48 - 9y)) + 7y = 30$

$2 (48 - 9 y) + 7 y = 30$ $2(48 - 9y) + 7y = 30$
$96 - 18 y + 7 y = 30$ $96 - 18y + 7y = 30$
$96 - 30 = 18 y - 7 y$ $96 - 30 = 18y - 7y$

$66 = 11 y$ $66 = 11y$

$6 = y$ $6 = y$

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How do you solve $2 x + 7 y = 30$ $2x + 7y = 30$ and $x = 48 - 9 y$ $x = 48 - 9y$ using substitution?

1 Answer

Explanation:

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Science

Math

Humanities

... and beyond

How do you solve 2x+7y=302x + 7y = 30 and x=48−9yx = 48 - 9y using substitution?

1 Answer

Explanation:

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How do you solve $2 x + 7 y = 30$ $2x + 7y = 30$ and $x = 48 - 9 y$ $x = 48 - 9y$ using substitution?