How do you solve the simultaneous equations $4 x + y = - 1$ $4x + y = -1$ and $4 x - 3 y = 7$ $4x - 3y = 7$ ?

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Answer 1 · 2018-05-20T17:45:59

$x = \frac{1}{4} and y = - 2$ $x = 1/4 and y = -2$

$4 x + y = - 1 - - - e q n 1$ $4x + y = -1 - - - eqn1$

$4 x - 3 y = 7 - - - e q n 2$ $4x - 3y = 7 - - - eqn2$

Subtracting $e q n 2$ $eqn2$ from $e q n 1$ $eqn1$

$(4 x - 4 x) + (y - (- 3 y)) = - 1 - 7$ $(4x - 4x) + (y - (-3y)) = -1 - 7$

$0 + y + 3 y = - 8$ $0 + y + 3y = -8$

$4 y = - 8$ $4y = -8$

$y = - \frac{8}{4}$ $y = - 8/4$

$y = - 2$ $y = -2$

Substiting the value of $y$ $y$ into $e q n 1$ $eqn1$

$4 x + y = - 1 - - - e q n 1$ $4x + y = -1 - - - eqn1$

$4 x + (- 2) = - 1$ $4x + (-2) = -1$

$4 x - 2 = - 1$ $4x - 2 = -1$

$4 x = - 1 + 2$ $4x = -1 + 2$

$4 x = 1$ $4x = 1$

$x = \frac{1}{4}$ $x = 1/4$

Therefore;

$x = \frac{1}{4} and y = - 2$ $x = 1/4 and y = -2$

How do you solve the simultaneous equations 4x + y = -14x+y=−14x + y = -1 and 4x - 3y = 74x−3y=74x - 3y = 7?