sovle by substution
posted by Geneva .
i don't get this whole concept whatsoever so lets start with problem one y= 3X +5
5 X  4y = 3

Your first equation tells a value for Y. Substitute that in the second equation.
5x  4(3x + 5) = 3
5x + 12x  20 = 3
17x = 20  3
17x = 17
x = 1
Now substitute 1 for x in the first equation to find a value for y.