x+14y=84
2x-7y= -7
Use substitution to solve for x.
I keep trying this and I get 8.3333333...
My teacher says its wrong.
What am I doing wrong?
How do I solve it?
+1904 \(x+14y=84\)
\(2x-7y=-7\)
In the first equation, solve for \(x\)
\(x-14y=84\)
add \(14y\) to both sides
\(x=84+14y\)
Now subsitute \(84+14y\) in the second equation where you see x
\(2(84+14y)-7y=-7\)
Distribute the \(2\)
\(168+28y-7y=-7\)
Now add \(28y\) and \(-7\) together
\(168+21y=-7\)
Now subtract \(168\) from both sides
\(21y=-175\)
Now divide \(21\) to both sides
\(y=\frac{-25}{3}\)
\(y=-\frac{25}{3}\)
In decimal form
\(y=-8.333333...\)
Solve the following system:
{x+14 y = 84
2 x-7 y = -7
In the first equation, look to solve for x:
{x+14 y = 84
2 x-7 y = -7
Subtract 14 y from both sides:
{x = 84-14 y
2 x-7 y = -7
Substitute x = 84-14 y into the second equation:
{x = 84-14 y
2 (84-14 y)-7 y = -7
2 (84-14 y)-7 y = (168-28 y)-7 y = 168-35 y:
{x = 84-14 y
168-35 y = -7
In the second equation, look to solve for y:
{x = 84-14 y
168-35 y = -7
Subtract 168 from both sides:
{x = 84-14 y
-35 y = -175
Divide both sides by -35:
{x = 84-14 y
y = 5
Substitute y = 5 into the first equation:
Answer: | {x = 14 y = 5
