SOLUTION: 8x+9y=11

Algebra ->  Functions -> SOLUTION: 8x+9y=11      Log On


   

Question 171788: 8x+9y=11
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Do you want to graph this?


8x%2B9y=11 Start with the given equation.


9y=11-8x Subtract 8x from both sides.


9y=-8x%2B11 Rearrange the terms.


y=%28-8x%2B11%29%2F%289%29 Divide both sides by 9 to isolate y.


y=%28%28-8%29%2F%289%29%29x%2B%2811%29%2F%289%29 Break up the fraction.


y=-%288%2F9%29x%2B11%2F9 Reduce.





In order to graph the equation y=-%288%2F9%29x%2B11%2F9, we only need two points to create a straight line




--------------------------------Let's find the first point--------------------------------

y=-%288%2F9%29x%2B11%2F9 Start with the given equation


y=-%288%2F9%29%287%29%2B11%2F9 Plug in x=7


y=-56%2F9%2B11%2F9 Multiply -8%2F9 and 7 to get -56%2F9


y=-45%2F9 Add


y=-5 Reduce


So when x=7, we have the value y=-5. This means we have the first point




--------------------------------Let's find the second point--------------------------------

y=-%288%2F9%29x%2B11%2F9 Start with the given equation


y=-%288%2F9%29%28-2%29%2B11%2F9 Plug in x=-2


y=16%2F9%2B11%2F9 Multiply -8%2F9 and -2 to get 16%2F9


y=27%2F9 Add


y=3 Reduce



So when x=-2, we have the value y=3. This means we have the second point




------------------------------------------------------------------------------------------------


So we have the two points: and


Now plot these two points on a coordinate system





Now draw a straight line through the two points. This line is the graph of y=-%288%2F9%29x%2B11%2F9

Graph of y=-%288%2F9%29x%2B11%2F9 through the two points and