How do you solve $9 x - 4 y = - 59$ $9x-4y = -59$ and $4 x + 27 = y$ $4x+27 = y$ using substitution?

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Answer 1 · 2016-08-26T15:13:37

$x = - 7$ $x=-7$ and $y = - 1$ $y=-1$

We have the first equation as $9 x - 4 y = - 59$ $9x-4y=-59$ and second equation $4 x + 27 = y$ $4x+27=y$ .

The second equation gives $y = 4 x + 27$ $y=4x+27$ and substituting this value of $y$ $y$ in first we get

$9 x - 4 (4 x + 27) = - 59$ $9x-4(4x+27)=-59$ or

$9 x - 16 x - 108 = - 59$ $9x-16x-108=-59$ or

$- 7 x = - 59 + 108 = 49$ $-7x=-59+108=49$ or

$x = - 7$ $x=-7$ and

$y = 4 \times (- 7) + 27 = - 28 + 27$ $y=4×(-7)+27=-28+27$

or $y = - 1$ $y=-1$

How do you solve 9x−4y=−599x-4y = -59 and 4x+27=y4x+27 = y using substitution?