Question

How do you solve x+y=4 and 5x−2y=−1?

Answer 1

Answer: $x=1 \\y=3$

Step-by-step explanation:

There are many methods to solve this but I think the SUBSTITUTION METHOD is the easiest so,

According to the question,

$x+y=4$      ---------(1)

$5x-2y=-1$ -----------(2)

Now, substituting the value of $x$

$x+y=4\\x=4-y$

Putting the above value of $x$ in equation (2):

$5x-2y=-1\\5(4-y)-2y=-1\\20-5y-2y=-1\\-7y=-1-20\\-7y=-21\\7y=21\\y=3$

Now, putting the value of $y$ in equation (1):

$x+y=4\\x+3=4\\x=4-3\\x=1$