Step-by-step explanation:
Realize that:
speed = distance / time and thus
time = distance / speed
Then the whole journey of 40/60 hours is the sum of (let's call them t1 and t2)
cycling: t1 = 2/y hours
running: t2 = 4/(y-4) hours
so we must simplify t1+t2=40 minutes (a.k.a. 4/6 hours):
2/y + 4/(y-4) = 4/6
let's multiply the first term by (y-4)/(y-4) and the second term by (y/y):
since they now share a common denominator:
cross-products:
further simplification:
q.e.d.
Answer:
See below
Step-by-step explanation:
<u>Assumed you need to solve the system:</u>
- 12x - 2y = - 1
- 4x + 6y = - 4
In order to solve this by elimination, triple the first equation and add the second one.
<u>It will make the coefficients of y same with opposite signs:</u>
When added together these cancel, leaving x as the only variable.
Look at the graphic I posted.Then go to this link:
Source:
https://astronomy.stackexchange.com/questions/19322/stellar-parallax
Answer:
±
,
Step-by-step explanation:
See the attached image
This problem involves Newton's 2nd Law which is: ∑F = ma, we have that the acting forces on the mass-spring system are: that correspond to the force of resistance on the mass by the action of the spring and that is an external force with unknown direction (that does not specify in the enounce).
For determinate we can use Hooke's Law given by the formula where correspond to the elastic constant of the spring and correspond to the relative displacement of the mass-spring system with respect of his rest state.
We know from the problem that an 15 Kg mass stretches the spring 1/3 m so we apply Hooke's law and obtain that...
Now we apply Newton's 2nd Law and obtaint that...
± =
Finally... ±
We know from the problem that there's not initial displacement and initial velocity, so... and
Finally the Initial Value Problem that models the situation describe by the problem is
Answer: 3a + 2c = 73 (last night)
2a + 5c = 89 (last week)
Step-by-step explanation: