Eccentricity = foci / half the length of the major axis
= 3.5 / 14 = 1/4
One way to go about this is to first list everything we know in the form of variables. This will make it easier to see how these numbers correlate instead of trying to remember formulas to plug these numbers into.
TimeA = 2.4h (time of Car A to travel)
TimeB = 4h (time of Car B to travel)
SpeedA = SpeedB + 22mph (Speed of Car A<span>)
</span>SpeedB = SpeedA - 22mph (Speed of Car B<span>)
</span>Distance = x (the distance traveled by each car)
We are looking for SpeedA. How can we find this? Well, we know that speed multiplied by time is equal to distance, so let's start there.
SpeedA * 2.4h = x
<span>(SpeedB + 22mph) * 2.4h = x
</span>(2.4h * SpeedB) + 52.8miles = x
We also know that:
SpeedB * 4h = x
Since both of these equations are equal to x, we can combine them:
SpeedB * 4h = x = <span>(2.4h * SpeedB) + 52.8miles
</span>SpeedB * 4h = <span>(2.4h * SpeedB) + 52.8miles
</span>1.6h * Speed B = 52.8miles
SpeedB = 52.8/1.6 mph = 33 mph
<span>SpeedA = SpeedB + 22mph = 33mph + 22mph = 55mph
</span>
Therefore, Car A was traveling at 55mph.
<span>(x-7)^2 = (x-7)(x-7) = x^2 -7x -7x +49 = x^2-14x+49</span>
answer is 'x^2+14x+49'
1 dozen = 12 apples.
3 apples cost 0.48, multiply that by 4 to get the price of 1 dozen.
0.48 x 4 = $1.92 per dozen.
Divide the total you can spend ( 3.84) by cost per dozen:
3.48 / 1.92 = 2
You can buy 2 dozen.
I'll assume the above equation is: 9 - 7x = 7 - 4(2x+3)
* do distributive multiplication
9 - 7x = 7 - 8x - 12
*move like terms
-7x + 8x = 7 - 12 - 9
* solve for x
x = 7 - 21
x = -14
To check, substitute x by its value -14
9 - 7x = 7 - 4(2x+3)
9 - 7(-14) = 7 -4[2(-14) + 3]
9 + 98 = 7 - 4(-28 +3)
107 = 7 - 4(-25)
107 = 7 + 100
107 = 107
