Step-by-step explanation:
step 1. #1 has no x
step 2. #2 has infinite solutions
step 3. #4 has y but no x
step 4. x^2 - x = 6 can be solved for x.
To solve for X you must get x by itself so let's get started
-4x+13=6x-7
subtract 13 from both sides
-4x=6x-20
subtract 6x from both sides
-10x=-20
divide both sides by -10
x=2
to check if this is correct plug in x into original equation
-4 (2)+13=6 (2)-7
-8+13=12-7
5=5
answer x=2 holds true :)
4/6
10/15
6/9
8/12
Hope these help you!!! =')