How do you solve this system of equations using the substitution method $x- y = 1 and 4x + 9y = - 87$ ?

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How do you solve this system of equations using the substitution method $x- y = 1 and 4x + 9y = - 87$ ?

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Answer 1 · 2018-08-13T07:31:27

$y=-7$
$x=-6$

Explanation:

Given -

$x-y=1$ ----------------(1)
$4x+9y=-87$ ----------(2)
Solve equation (1) for $x$
$x=1+y$
Substitute $x=1+y$ in equation (2)
$4(1+y)+9y=-87$
$4+4y+9y=-87$
$13y=-87-4=-91$
$y=(-91)/13=-7$

$y=-7$

Substitute $y=-7$ in equation (1)

$x-(-7)=1$
$x+7=1$
$x=1-7=-6$

$x=-6$

Answer 2 · 2018-08-13T07:37:30

$x=-6 and y=-7$

Explanation:

Here ,

$x-y=1 =>x=y+1.....to(1)$

$4x+9y=-87.................to(2)$

Substitute value of $x$ from $(1)$ into $(2)$

$4(y+1)+9y=-87$

$4y+4+9y=-87$

$13y=-91$

$:.color(red)(y=-7$

Subst. $color(red)(y=-7$ into (1)

$x=color(red)(-7)+1=>color(blue)(x=-6$

Hence , $x=-6 and y=-7$

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How do you solve this system of equations using the substitution method $x- y = 1 and 4x + 9y = - 87$ ?

2 Answers

Explanation:

Explanation:

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Science

Math

Humanities

... and beyond

How do you solve this system of equations using the substitution method x- y = 1 and 4x + 9y = - 87x- y = 1 and 4x + 9y = - 87?

2 Answers

Explanation:

Explanation:

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How do you solve this system of equations using the substitution method $x- y = 1 and 4x + 9y = - 87$ ?