# Math Help - couple problems math help

1. ## couple problems math help

Solve each system by the substitution method .Indicate whether each system is independent, inconsistent, or dependent.

1) 3y=x+5
2x-2y= -10

2) x=1/8y-1
y= 1/4x+39

2. Originally Posted by fancyface
1) 3y=x+5
2x-2y= -10
In first equation we have,
$x=3y-5$
Substitute,
$2(3y-5)-2y=-10$
$6y-10-2y=-10$
$4y=0$
$y=0$
$x=-5$

There is a unique solution.

3. Originally Posted by fancyface
Solve each system by the substitution method. ...
2) x=1/8y-1
y= 1/4x+39
Hello,

you have $x=\frac{1}{8}y-1$. Substitute the x in the 2nd equation:

$y=\frac{1}{4} \cdot \left( \frac{1}{8}y-1 \right) +39$. Expand the RHS of this equation:

$y=\frac{1}{32}y-\frac{1}{4} +39$. This will give:

$\frac{31}{32}y=\frac{155}{4}$. Solve for y. I've got y = 40. Re-substitute this value in equation#1. I got x = 4.

There is only this solution.

EB