Question

Solve the system of equations.

5x + y = 9
3x + 2y = 4  

A) (-2, 5)

 
B) (1, 4)  
C) (2, -1)
D) (4, -4)

Answer 1

you can find replcing x and y by the coordinates of the points
A : 5.-2 + 5 ≠9 not solution
B : 5.1 + 4 = 9 so 3.1 + 2.4 = 11 ≠4 not solution
C: 5.2 + = 9 so 3.2 + 2.-1 = 4 both are right then C is solution
D: 5.4 - 4 = 16 ≠ 9 not solution

Answer 2

(C) (2,-1)

Explanation:

The given system of equations is :

`5x+y=9` (1)

and
`3x+2y=4` (2)

Multiply equation (1) with 2 and then subtract equation (2) from it, we get

⇒
`10x+2y-3x-2y=18-4`

⇒
`7x=14`

⇒
`x=2`

Substitute the value of x=2 in equation (1), we get

⇒
`5(2)+y=9`

⇒
`10+y=9`

⇒
`y=-1`

Therefore, x=2 and y=-1. that is (2,-1).