How do you solve $5 x + 8 y = 7$ $5x + 8y = 7$ and $x + y = 2$ $x + y = 2$ using substitution?

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How do you solve $5 x + 8 y = 7$ $5x + 8y = 7$ and $x + y = 2$ $x + y = 2$ using substitution?

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Answer 1 · 2016-04-24T13:22:42

x=3, y= -1

Explanation:

given x+y=2
y= 2 - x (eq. 1)

given 5x+8y=7 (eq.2)

substitute eq. 1 in eq. 2

5x + 8(2-x) =7
5x + 16 - 8x = 7 (open the bracket)
-3x=7-16= -9
x= -9/ -3 = 3

eq 1-
y= 2-3= -1

so x=3, y= -1

Answer 2 · 2016-04-24T13:23:00

$(x, y) = (3, - 1)$ $(x,y)=(3,-1)$
See below for method of solution by substitution.

Explanation:

If $x + y = 2$ $x+y=2$
then $y = 2 - x$ $y=2-x$
and
$XXX (2 - x)$ $color(white)("XXX")(2-x)$ can be substituted for $y$ $y$ in $5 x + 8 y = 7$ $5x+8y=7$

This would give:
$XXX 5 x + 8 (2 - x) = 7$ $color(white)("XXX")5x+8(2-x)=7$

$XXX 5 x + 16 - 8 x = 7$ $color(white)("XXX")5x+16-8x=7$

$XXX - 3 x = - 9$ $color(white)("XXX")-3x=-9$

$XXX x = 3$ $color(white)("XXX")x= 3$

Then, returning to $y = 2 - x$ $y=2-x$
we have
$XXX y = 2 - 3 = - 1$ $color(white)("XXX")y=2-3 =-1$

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How do you solve $5 x + 8 y = 7$ $5x + 8y = 7$ and $x + y = 2$ $x + y = 2$ using substitution?

2 Answers

Explanation:

Explanation:

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