Which relationship of angle a is correct? A. Cos(a) = 3/5 B. Cos(a) = 4/3 C. Sin(a) = 3/5 D. Sin(a) = 4/3
1 answer:
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Let's write some equations.
Mingwei's distance from Town A after
hours from 8:00 is 
.
Ali's distance from Town B after hours is 
, since he doesn't start walking for 40 minutes.
When Mingwei's distance is twice Ali's, they've met up (since their distance from Town A is twice their distance from Town B).
So, this gives
, so 
, so 
, so the time is 10:40.
After
hours, Mingwei has traveled 
kilometers while Ali has traveled sixty, so the distance between the towns is 
kilometers.
Mingwei's distance from Town A after
Ali's distance from Town B after
When Mingwei's distance is twice Ali's, they've met up (since their distance from Town A is twice their distance from Town B).
So, this gives
After
A system of equations with infinitely many solutions is a system where the two equations are identical. The lines coincide. Anything that is equal to 
will work. You could try multiply the entire equation by some number, or moving terms around, or adding terms to both sides, or any combination of operations that you apply to the entire equation.
You could multiply the whole thing by 4.5 to get
. If you want, you could mix things up and write it in slope-intercept form: 
. The point is, anything that is equivalent to the original equation will give infinitely many solutions x and y. You can test this by plugging in values x and y and seeing the answers!
The attached graph shows that four different equations are really the same.
You could multiply the whole thing by 4.5 to get
The attached graph shows that four different equations are really the same.