Question

Is the ordered pair (1, -5) is a solution for the system x + 2y = -9 and x - y = 6.

1. Yes
2. No

Answer 1

A yes

Answer 2

Plug the value of x =1 in both equations. If both equations give back the value of y = -5
then (1, -5) is a solution

Answer 3

For x + 2y = -9 a
substitute for x =1
=> 1 +2y = -9
=> 2y = -10
=> y = -5

and also
for x - y = 6.
substitute for x =1
=> 1-y =6
=> -y =5
=> y = -5

Hence both equations satisfy ( 1, -5)

Answer 4

Alternatively simplfy the system further to yield one equation:

i.e.

x + 2y = -9 (1)
x - y = 6. (2)

subtract equation (2) from equation (1)
=> x + 2y = -9 - (x - y = 6)
=> 3y = -15
=> y = - 5

Now plug y = -5 in any one of the origal equations
Thus if we choose equation (1)
then x +2(-5) = -9
=> x -10 = -9
=> x =1

Hence the solution to the system of the equations is

(1, -5)

Answer 5

Just remember the ordered pai ( 1, -5) => when x = 1, the value of y = -5
Ordered pair is usually written as ( x, f(x)) = ( x, y)