<span>-2x^2 + 10x + 9 =0
multiply whole equation by -1
2x^2 -10x -9 =0
(sqrt2x)^2 -2(sqrt2x)(5/</span>sqrt2) -9=0
add (5/sqrt2)^2 on both sides
(sqrt2x)^2 -2(sqrt2x)(5/sqrt2) + (5/sqrt2)^2-9=(5/sqrt2)^2
a^2-2ab+b^2=(a-b)^2
(sqrt2x - 5/sqrt2)^2=(5/sqrt2)^2+9
(sqrt2x - 5/sqrt2)^2=21.5
taking squareroot on both sides
sqrt2x - 5/sqrt2 = +-4.64
so
sqrt2x - 5/sqrt2 = +4.64 or sqrt2x - 5/sqrt2 = -4.64
sqrt2x = 4.64 + 5/sqrt2 sqrt2x = -4.64 + 5/sqrt2
sqrt2x =8.18 sqrt2x = -1.1045
x=8.18/sqrt2 x= -1.1045/sqrt2
x=5.78 x=-0.781
Answer:
A: 68.25 minutes
B: 12 times
C: 42 mins and you decide this part I actually don't know. But I think it could be reasonable, after 40 times someone should get pretty good at it.
Step-by-step explanation:
a: 72 -0.75*5 = 68.25
b: M=63=72-0.75n
subtract 72 from each side: -9 = -0.75n
divide each side by -0.75: n = 12
so 12 times
c: 72 - 0.75(40) = 42 minutes. Now this could be is reasonable, but we don't know what their desert is. But 40 times is a lot of practice.
B) thats the only one i could think of that would even sound right
The area of the square increasing at 30 
The rate of change function is defined as the rate at which one quantity is changing with respect to another quantity. In simple terms, in the rate of change, the amount of change in one item is divided by the corresponding amount of change in another
Let the side of a square be x.
So,
Area of square = 
A =
Differentiating with respect to time we get,
dA/dt = 2x dx/dt
When area = 9 
the side becomes 3 cm
At x = 3cm and dx/dt = 5 cm/s (Given)
dA/dt = 2.3.5 = 30
Thus the area of the square increasing at 30
Learn more about rate of change here :
brainly.com/question/12786410
#SPJ4
Answer: no cheating on the state test
Step-by-step explanation:
