Answer:
Step-by-step explanation:
Let the speed of the car is c and speed of the plane is p.
<h3>We are given:</h3>
The speed of the plane is 7 times the speed of the car
The distance traveled is
The time difference to travel this same distance is 3 hours.
<h3>We know that:</h3>
- d = ts, where d- distance, t- time, s - speed
Find the time for car and plane and their difference.
<h3>Car</h3>
<h3 /><h3>Plane</h3>
- t = d/s = 315/p = 315/(7c) = 35/c
<h3 /><h3>The difference</h3>
<u>Solve it for c:</u>
- (315 - 45)/c = 3
- 270/c = 3
- c = 270/3
- c = 90 km/h
Now find the speed of plane:
As we see, Jenny is right
Answer:
.5 and .5, .75 and .25, ect
The tangent line to <em>y</em> = <em>f(x)</em> at a point (<em>a</em>, <em>f(a)</em> ) has slope d<em>y</em>/d<em>x</em> at <em>x</em> = <em>a</em>. So first compute the derivative:
<em>y</em> = <em>x</em>² - 9<em>x</em> → d<em>y</em>/d<em>x</em> = 2<em>x</em> - 9
When <em>x</em> = 4, the function takes on a value of
<em>y</em> = 4² - 9•4 = -20
and the derivative is
d<em>y</em>/d<em>x</em> (4) = 2•4 - 9 = -1
Then use the point-slope formula to get the equation of the tangent line:
<em>y</em> - (-20) = -1 (<em>x</em> - 4)
<em>y</em> + 20 = -<em>x</em> + 4
<em>y</em> = -<em>x</em> - 24
The normal line is perpendicular to the tangent, so its slope is -1/(-1) = 1. It passes through the same point, so its equation is
<em>y</em> - (-20) = 1 (<em>x</em> - 4)
<em>y</em> + 20 = <em>x</em> - 4
<em>y</em> = <em>x</em> - 24
If you looked it up online you could find it. look on safari
Depending on what you're supposed to do, the three could either mean to distribute it into the equation, giving you
either
(3*2015) or (3*20)*(3*15) or (3*20) +/- (3*15)
Or an example of factoring where they took 3 out of 60 and 45.
There are no instruction on what to do in this question.
