Posted by Daisy on .
I'm really confused on substitution. My teacher has a terrible accent and cannot understand what she says. i get the basics myself but i'm pretty confused on the following problems:
1) y= 3x  8
y= 4x
2) 2x + 7y = 3
x=1 4y
3) x = 2y
4x + 2y = 15
Any help. I know i should probably know this by now. i started mid term :/

algebra 
PsyDAG,
3. Substitute 2y for x in the second equation.
4(2y) + 2y = 15
Solve for y. Put that value in the first equation to solve for x. Check by putting both values in the second equation.
You can substitute either x or y value from one equation to the other to solve.
Use these steps in doing the first two problems. I hope this helps.