Three times of five is more than half of a number. What's the number,

Three times of five is more than half of a number. What's the number,

Let this number be X
5*3=X/2+8
15=X/2+8
X/2=7
X=14

Five times of a number minus 12 is equal to three times of this number. How much is this number? Solve the equation

Let this number be X
5x-12=3x
5x-3x=12
2x=12
x=12÷2
x=6
So the number is 6

If you subtract 18 from a number and multiply it by 9, the product is six times that number. What's the number? (equation)

Let this number be X
(x-18)×9=6x
　　9x-162=6x
　　3x=162
x=162÷3
　　x=54

A number minus 5 / 2 equals 1.44. What's the number

Let X be the number
x-5/2x=1.44
-3/2x=1.44
x=-0.96

It is known that the bottom area and side area of a cylinder are the same. If the height of the cylinder is 5cm, then its volume is () square centimeter (& nbsp; take 3.14)
A. 314B. 1570C. 3140D. 157

Base area = side area, so radius × radius × π = 2 × radius × π × height, from which we can get: radius = 2 × height, because height is 5cm, so radius is: 2 × 5 = 10 (CM); volume of cylinder is: 3.14 × 102 × 5 = 1570 (cm3); answer: volume of cylinder is 1570 cm3

If we know that the quadratic power of X + 3x + 5 = 7, then the quadratic power of X + 3x = (), 3 (the quadratic power of X + 3x) - 2 = ()

2,4

A is an integer. Can you say that a + a must be divisible by 2?
A is an integer. Can you say that a * a (the second power of a) + a must be divisible by 2?

A is even
a=2k,
A ^ 2 + a = a (a + 1) = 2K (2k + 1) can be divisible by 2
A is odd
a=2k+1
A ^ 2 + a = (2k + 1) (2k + 2) = 2 (2k + 1) (K + 1) can be divisible by 2
A is an integer, a + a must be divisible by 2

Let F1F2 be the focus of the ellipse x ^ 2 + 3Y ^ 2 = 3, and point p be the point on the ellipse. If ∠ f1pf2 = 90 °, how many points are there
P: how many

Knowledge point: let p be a point on the ellipse, then when p is the endpoint of the minor axis, ∠ f1pf2 is the largest, when p is the endpoint of the major axis, ∠ f1pf2 is the smallest, which is 0. Therefore, the range of ∠ f1pf2 is [0, θ], where θ = ∠ f1bf2, B is an endpoint of the minor axis
In this problem, the ellipse X & # 178; + 3Y & # 178; = 3 is transformed into the standard equation: X & # 178; / 3 + Y & # 178; = 1, so a = √ 3, B = 1, C = √ 2
Let B be an endpoint of the minor axis of the ellipse

The sum of the reciprocal of two prime numbers is 24 / 143. What are the two prime numbers

143=11×13
24/143=1/11+1/13
So 11 and 13

The solution of the inequality loga (x + 1) - loga (x-1) ≥ 0 with respect to x,

loga(x+1)-loga(x-1)≥0
loga(x+1)≥loga(x-1)
When a > 1, the original inequality is
{x+1≥x-1
{x+1>0
{x-1>0
The solution is x > 1
The solution set of the original inequality is (1, + ∞)
When 00
The solution is x ∈Φ
∴0