SOLUTION: graph the following inequality on a plane; 3x+4y is less than or equal to 12

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Question 147908: graph the following inequality on a plane; 3x+4y is less than or equal to 12
Answer by mangopeeler07(462) About Me  (Show Source):
You can put this solution on YOUR website!
First you have to get the equation into y=mx+b form. 3x%2B4y%3C=12. First change it to 3x%2B4y=12. Then solve for y and get y=-%283%2F4%29x%2B3. Graph that line:
Solved by pluggable solver: DESCRIBE a linear EQUATION: slope, intercepts, etc
Equation 3+x+%2B+4+y+=+12 describes a sloping line. For any
equation ax+by+c = 0, slope is -a%2Fb+=+-3%2F4.
  • X intercept is found by setting y to 0: ax+by=c becomes ax=c. that means that x = c/a. 12/3 = 4.
  • Y intercept is found by setting x to 0: the equation becomes by=c, and therefore y = c/b. Y intercept is 12/4 = 3.
  • Slope is -3/4 = -0.75.
  • Equation in slope-intercept form: y=-0.75*x+3.
graph%28+500%2C+500%2C+4-8%2C+4%2B8%2C+3-8%2C+3%2B8%2C+-0.75%2Ax%2B3+%29+


Now since it was originally 3x%2B4y%3C=12, shade every part of the graph under that line. Then you're done.
If you still need help, visit my lesson on graphing inequalities:
http://www.algebra.com/algebra/homework/Graphs/Inequalities-Made-Easy.lesson