What's the difference between i loved and i have loved?

Explanation:

I have loved him before and I loved him have basically the same meanings, but they are written in differentEnglish tenses. I HAVE LOVED HIM BEFORE is written in present perfect tense. I LOVED HIM is written in simple past tense. ... I have loved him before means that I loved him at an unspecified time before the present.

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4