## anonymous 4 years ago need to find m so that y=mx+5 has a common intersection point with y=7x+43 and y=8x+53

1. anonymous

Do you mean same common intersection point

2. anonymous

If no all values of m except 7,8

3. anonymous

i need to find a value for the slope for thee first equation so it has a common intersection point with the other 2

4. anonymous

m=16/5

5. anonymous

unfortunately that didn't solve it

6. Mr.Math

Do you know how to find the intersection point of the two given lines?

7. Mr.Math

I mean y=7x+43 and y=8x+53.

8. Mr.Math

The two lines intersect $$7x+43=8x+53 \implies x=-10$$. Substitute $$x=-10$$ in either equation you get $$y=-70+43=-27$$. So the intersection point is $$-10,-27$$. Plug this point in the first equation and solve for m.

9. anonymous

Mr Math says the same

10. anonymous

I did it using determinats

11. Mr.Math

Yes, NotSObright is so bright and he's right.

12. Mr.Math

You basically have to solve: $-27=-10m+5 \implies m=\frac{32}{10}=\frac{16}{5}.$

13. anonymous

my mistake. Thank you to both of you. The online program I use is picky... did not have to simplify to 16/5. successful using 32/10