Question

Solve the simultaneous equations

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

Answer 1

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)

Answer 2

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