Need help

[homeschool mom]

Line m has the equation y = 3x + 5. Line n has the equation y = kx - 7. Lines m and n intersect at the point (-4, -7). What is the value of k?

 

[lev888]

Plug in -4 and -7 into the second equation. Solve for k.

 

[JeffM]

Line m has the equation y = 3x + 5. Line n has the equation y = kx - 7. Lines m and n intersect at the point (-4, -7). What is the value of k?

Here is how to think about this problem.

If lines m and n intersect at (-4, 7), then point (-4, 7) lies on BOTH lines. Makes sense, right?

That means that point lies on line n. Thus,

[MATH]7 = k * (-\ 4) - 7.[/MATH]
Now solve for k.

Actually part of this problem involves determining what information is relevant. The only relevance of line m in this problem is that it intersects with line n at the given point. The equation for line m is irrelevant. Frequently an important part of solving a problem, particularly problems in real life, is figuring out what is irrelevant.

 

[homeschool mom]

Here is how to think about this problem.

If lines m and n intersect at (-4, 7), then point (-4, 7) lies on BOTH lines. Makes sense, right?

That means that point lies on line n. Thus,

[MATH]7 = k * (-\ 4) - 7.[/MATH]
Now solve for k.

Actually part of this problem involves determining what information is relevant. The only relevance of line m in this problem is that it intersects with line n at the given point. The equation for line m is irrelevant. Frequently an important part of solving a problem, particularly problems in real life, is figuring out what is irrelevant.

there were a few typos but i plugged in the correct numbers ...thank you for your help