Hello,
2x-5y=1 |3|4
3x-4y=-2|-2|-5
------------------------
-7y=7 ==>y=-1
-7x=14==>x=-2
sol={(-2,-1)}
Find their lcm which is 4m then multiply
8m=44
m=44/8 or 5.5
Absolute value is always positive because its talking about the real distance or steps to zero and even when you at a negative number it takes real steps to get back to zero.
Move constant to other side
add 1
4c^2-8c=1
divide by 4 to make leading coeficient 1
c^2-2c=1/4
take 1/2 of linear coeficient and square it
-2/2=-1, (-1)^2=1
add that to both sides
c^2-2c+1=1/4+1
factor perfect squaer and add
(c-1)^2=5/4
square root both sides
c-1=+/-(√5)/2
add 1
c=1+/-(√5)/2
c=2.12 or -0.12