Question

Substitution method6x-7y=5,3x+y=-1​

Answer 1

Answer:

$x = - \frac{2}{27}$

$y = - \frac{4}{5}$

Step-by-step explanation:

Lets call

$6x - 7y = 5$

equation 1

$3x + y = - 1$

equation 2

using equation 2, we would make y the subject of the formula as it would be easier

$y = - 1 - 3x$

This would now be called our equation 3

Now the next step is to substitute equation 3 in equation 1

$6x - (7( - 1 - 3x)) = 5$

$6x - ( - 7 - 21x) = 5$

$6x + 7 + 21x = 5$

$27x = 5 - 7$

$27x = - 2$

Divide both sides by 27$\frac{27x}{27} = - \frac{2}{27}$

$x = \frac{ - 2}{27}$

Substitute the value of x in equation 2

$3( \frac{ - 2}{27} ) + y = - 1$

$- \frac{ 2}{9} + y = - 1$

$y = - 1 + \frac{2}{9}$

$y = - \frac{ 8}{10}$

$y = - \frac{4}{5}$