Here are the 4 inequality signs.

---> a is less than b

---> a is less than or equal to b

---> a is greater than b

---> a is greater than or equal to b
For the second and fourth lines above, the two sides may or may not be equal.
For the first and third lines above, the two sides cannot be equal.
First, multiply 4*2x-4*-5= 8x-20.
Second, add 15 to 8x-20
Third, that would equal 8x-20+15=11
Fourth, 15+-20= -5
Fifth, 8x-5=11
Sixth, add +5 to -5 and +5 to 11= 8x=16
Last, do 8x/8x and 16/8x
The answer is x=2
2x+y=5
To put this in slope intercept form, you simply have to get y by itself on the left side of the equation.
2x+y=5
2x+y-2x=5-2x
y=-2x+5
Now, I had to switch the right side around like that, because slope intercept form is y=mx+b
Because you're subtracting 2x from 5, it becomes 5 added to -2x when it's put in the correct form.
y=-2x+5