Question

Solve the simultaneous equations

5x+2y=18
4x-2y=0

Answer 1

Add the equations
It will be
9x = 18
So x=2
And putting value of x in eq 2
4*2-2y = 0
2y = 8
y = 4

Answer 2

Since the order of equations makes us able to add al the like terms 5x + 4x;      2y + (- 2y); 18 + 0:

 $5x + 2y = 18$

             +

 $4x - 2y = 0$

             =

        $9x = 18$

(We got that answer by summing the two equations. Note that 2y + (-2y) cancels out since it results in 0)

$9x = 18$ → we take 9 to the right side of the equation

$x = 18 / 9$ → we solve for 18 / 9

$\bf~x = 2$ → final answer

Answer for x:

$\boxed{\bf~x=2}$

Now to solve for y we substitute all the x's by 2 in any of the equations you like, I'll choose the first one:

$5(2) + 2y = 18$ → we solve for 5(2)

$10 + 2y = 18$ → we take 10 to the right side of the equation

$2y = 18 - 10$ → we solve for 18 - 10

$2y = 8$ → we take 2 to the right side of the equation

$y = 8 / 2$ → we solve for 8 / 2

$\bf~y=4$ → final answer

Answer for y:

$\boxed{\bf~y = 4}$

Hope it helped,

BioTeacher101

(If you have any questions, feel free to ask them in the comments)