40% x + 24 = 2x to solve the equation

40% x + 24 = 2x to solve the equation

40%x+24=2x
0.4x+24=2x
2x-0.4x=24
1.6x=24
x=15

Solving equation (40-x) (64-2x) = 2418

Solving the equation
（40-x）（64-2x）=2418
（40-x）（32-x）=1209
x²-72x+1280=1209
x²-72x+71=0
(x-1)（x-71)=0
x=1 x=71

2X + 40% x = 2:5 to solve the equation

2x+40％x=2:5
2x+0.4x=2:5
2.4x=2:5
2.4x*5=2
12x=2
x=1/6
Do not know, welcome to ask

Now that science and technology are so advanced, what is the purpose of human development?
Why? Why

In order to make technology more developed

The PI is round______ And______ What's the ratio? What's the ratio______ ．

From the meaning of PI, we can see that: Pi represents the ratio of the circumference of a circle to its diameter, and the value of PI is π; so the answer is: circumference, its diameter, π

There is a cylinder whose bottom area is exactly equal to the side area. If the bottom area of the cylinder remains unchanged, the height of the cylinder increases by 1.5 cm,
Its surface area is increased by 56.52 square centimeters. What is the surface area of the original cylinder?
Formula, come on

Bottom circumference = 56.52 △ 1.5 = 37.68 (CM)
Bottom radius = 37.68 △ 3.14 △ 2 = 6 (CM)
Bottom area = 3.14 × 6 & # 178; = 113.04 (cm2)
The surface area of the original cylinder = 113.04 × 3 = 339.12 (square centimeter)

Let f (x) = 3 to the power of X + 3x-8, and use the dichotomy to find the power of X + 3x-8 = 0 of equation 3 in the process that x belongs to the approximate solution of (1,2)
Calculated to f (1) 0f (1.25)

F (1) 0, then the root is (1,1.5)
f(1.5)>0f(1.25)

Let n be an integer to show that (2n + 1) 2 - 25 can be divided by 4

It is proved that: ∵ (2n + 1) 2-25, = 4n2 + 1 + 4n-25, = 4 (N2 + n-6); (2n + 1) 2-25 can be divisible by 4

If F1F2 is the two focal points of the ellipse x2 + 2Y2 = 2, and P is a moving point on the ellipse, then the absolute value of vector Pf1 + vector PF2 is
Minimum,,, vector inequality calculation application? No one will?

The elliptic equation is reduced to x ^ 2 / 2 + y ^ 2 = 1, so a ^ 2 = 2, B ^ 2 = 1, C ^ 2 = a ^ 2-B ^ 2 = 1,
So a = √ 2, B = C = 1, F1 (- 1,0), F2 (1,0),
Let P (x, y), then Pf1 = (- 1-x, - y), PF2 = (1-x, - y),
So | Pf1 + PF2 | ^ 2 = (- 2x) ^ 2 + (- 2Y) ^ 2 = 4 (x ^ 2 + y ^ 2)
=4(x^2+1-x^2/2)=4+2x^2 ,
By 0

The sum of three different primes is 14. What is the product of these three primes?

The three prime numbers are 2, 5 and 7, so the product is 70