Answer: 4.2 miles
Step-by-step explanation:
So she ran 6 miles in 50 minutes how long will she run in 35 minutes?
So the equation will therefore be:
6=50
x=35
Cross multiply
6 x 35 = 50x
210 = 50x
Divide both sides by 50
The answer is 4.2 miles
Multiply the original DE by xy:
xy2(1+x2y4+1−−−−−−−√)dx+2x2ydy=0(1)
Let v=xy2, so that dv=y2dx+2xydy. Then (1) becomes
x(y2dx+2xydy)+xy2x2y4+1−−−−−−−√dxxdv+vv2+1−−−−−√dx=0=0
This final equation is easily recognized as separable:
dxxln|x|+CKxvKx2y2−1K2x4y4−2Kx2y2y2=−dvvv2+1−−−−−√=ln∣∣∣v2+1−−−−−√+1v∣∣∣=v2+1−−−−−√+1=x2y4+1−−−−−−−√=x2y4=2KK2x2−1integrate both sides
Answer: Option C) Raj forgot the negative when substituting -15+9x for y.
Solution:
(1) 9x-y=15
(2) 2x+8y=28
Isolating y in the first equation. Subtracting 9x both sides of the equation:
(1) 9x-y-9x=15-9x
Subtracting:
(1) -y=15-9x
Multiplying both sides of the equation by -1:
(1) (-1)(-y)=(-1)(15-9x)
(1) y=-15+9x
Then Raj found the value of y. It's not option D.
Substitutng y by -15+9x in the second equation:
(2) 2x+8(-15+9x)=28
Then option C) is the answer: Raj forgot the negative when substituting -15+9x for y.
Eliminating the parentheses applying the distributive property in the multiplication:
(2) 2x-120+72x=28
Adding similar terms:
(2) 74x-120=28
Solving for x. Adding 120 both sides of the equation:
(2) 74x-120+120=28+120
Adding:
(2) 74x=148
Dividing both sides of the equation by 74:
(2) 74x/74=148/74
Dividing:
(2) x=2
Solving for y: Replacing x by 2 in the first equation:
(1) y=-15+9x
(1) y=-15+9(2)
Multiplying:
(1) y=-15+18
Subtracting:
(1) y=3
(s + 3t) * (2s - 2t) = 2s^2 - 2st + 6ts - 6t^2
The first digit can be any one of the numbers 2-9 That a total of 8 numbers.
The next 6 digits can be any permutation of 6 from the numbers 0 to 9.
(10 numbers)
nPr = n! / r!
so here we have 10P6 = 10! / 6! = 10*9*8*7 = 5040
So final answer is 8 * 5040 = 40,320
