SOLUTION: Given the following system of linear equation, make comment about the lines and the number of solutions this system has. y = -3x - 12 y = 2x + 12

Algebra ->  Linear-equations -> SOLUTION: Given the following system of linear equation, make comment about the lines and the number of solutions this system has. y = -3x - 12 y = 2x + 12       Log On


   



Question 229937: Given the following system of linear equation, make comment about the lines and the number of solutions this system has.
y = -3x - 12
y = 2x + 12

Found 2 solutions by drj, stanbon:
Answer by drj(1380) About Me  (Show Source):
You can put this solution on YOUR website!
Given the following system of linear equation, make comment about the lines and the number of solutions this system has.
y = -3x - 12 Equation A
y = 2x + 12 Equation B

Step 1. The above lines in given in slope intercept form given as y=mx+b where m is the slope and b is the y-intercept when x=0 or at point (0,b).

Step 2. The slope of Equation A is m1=-3 and the slope of Equation B is m2=2. So they are not parallel since the parallel lines have the same slope. The lines are not perpendicular since the product of their slopes is not equal to -1 since m1*m2 does not equal -1.

Step 3. The lines intersect at a point so there is one solution.

Here's a graph of the two lines

graph%28600%2C600%2C-15%2C15%2C-15%2C15%2C+-3x-12%2C+2x%2B12%29

The intersection between these two lines is given below using substituion:

Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
+system%28+%0D%0A++++3%5Cx+%2B+1%5Cy+=+-12%2C%0D%0A++++-2%5Cx+%2B+1%5Cy+=+12+%29%0D%0A++We'll use substitution. After moving 1*y to the right, we get:
3%2Ax+=+-12+-+1%2Ay, or x+=+-12%2F3+-+1%2Ay%2F3. Substitute that
into another equation:
-2%2A%28-12%2F3+-+1%2Ay%2F3%29+%2B+1%5Cy+=+12 and simplify: So, we know that y=2.4. Since x+=+-12%2F3+-+1%2Ay%2F3, x=-4.8.

Answer: system%28+x=-4.8%2C+y=2.4+%29.



Same results as before.

I hope the above steps and explanation were helpful.

For Step-By-Step videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and for Trigonometry please visit http://www.FreedomUniversity.TV/courses/Trigonometry.

Also, good luck in your studies and contact me at john@e-liteworks.com for your future math needs.

Respectfully,
Dr J

http://www.FreedomUniversity.TV

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The slopes are different so there is one solution.
Cheers,
Stan H.