How do you solve the system $y = 5 x - 7$ $y = 5x - 7$ and $- 4 + y = - 1$ $-4 + y = -1$ by substitution?

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Answer 1 · 2015-05-21T08:16:45

$y = 5 x - 7$ $y = 5x - 7$ ..........equation $(1)$ $(1)$

$- 4 + y = - 1$ $-4 + y =-1$ ......equation $(2)$ $(2)$

substituting equation $(1)$ $(1)$ in equation $(2)$ $(2)$

$- 4 + y = - 1$ $-4 + y =-1$
$- 4 + (5 x - 7) = - 1$ $-4 + (5x -7)= -1$
$5 x - 11 = - 1$ $5x -11= -1$
$5 x = 10$ $5x = 10$
$x = 2$ $x = 2$

substituting the value of $x$ $x$ in equation $(1)$ $(1)$
$y = 5 x - 7 = 5 . (2) - 7$ $y = 5x - 7 = 5.(2) -7$
$y = 10 - 7 = 3$ $y = 10 -7 = 3$

The solutions for the system of equations are :
$x = 2$ $color(blue)x=2$
$y = 3$ $color(blue)y=3$

How do you solve the system y=5x−7y = 5x - 7 and −4+y=−1-4 + y = -1 by substitution?