The number of class one is 1.2 times that of class three. Class two has three fewer people than class three. There are 157 people in three classes. How many people are there in three classes

The number of class one is 1.2 times that of class three. Class two has three fewer people than class three. There are 157 people in three classes. How many people are there in three classes

There are 60 people in class one, 47 people in class two and 50 people in class three

There are three classes in grade five. Class one accounts for 25% of the total. The ratio of class two to class three is 7:8, and class one is 24 less than class three,

Class 2 and class 3 account for 1-25% of the total number = 75%
75%÷（7+8）=5%
5%×7=35%
5%×8=40%
24÷（40%-25%）
=160

It is known that the definition field of function f (x) = 2asin (2x - 3 / π) + B is {0, 2 / π}. The maximum value of function is 1 and the minimum value is - 5. Find the value of a and B
Because x belongs to [0, π / 2], then (2x - π / 3) belongs to [- π / 3,2 π / 3]. Why is it concluded that sin (2x - π / 3) belongs to [- √ 3 / 2,1]

∵x∈[0,π/2] ∴(2x-π/3)∈[-π/3,2π/3]
When x ∈ [0, π / 2], sin (2x - π / 3) ∈ [- √ 3 / 2,1] is an increasing function
When a > 0, f (x) ∈ [- √ 3A + B, 2A + b]
The maximum value of ∵ function is 1, and the minimum value is - 5 ∵ 3A + B = 1, 2A + B = - 5 ∵ a = - 6 / (2 + 3) < 0
∴a＜0 ∴f(x)∈[2a＋b,﹣√3a＋b] ∴﹣√3a＋b＝﹣5 2a＋b＝1
∴a＝6(2－√3) b＝12√3－23

Mathematical quadratic function: no matter what the value of M is, the vertex of parabola y = x2-2mx + M2 + 2m-1 is on the same line. Find the analytical formula of the line

Y = x2-2mx + M2 + 2m-1 = = = > y = (x-m) ^ 2 + 2m-1, the vertex is (m, 2m-1)
The elimination of m by x = m, y = 2m-1,
We get y = 2x-1
Y = 2x-1 is the path of the vertex

It is known that the rational number a satisfies the cubic power of a plus the square of 3A plus 3A plus 2 = 0, and the power of (a + 1) 2002 plus (a + 1) 2003 plus (a + 1) 2004

A ^ 3 + 3A ^ 2 + 3A + 2 = 0 (a ^ 3 + 1) + (3a ^ 2 + 3a) + 1 = 0 (a + 1) (a ^ 2-A + 1) + 3A (a + 1) + 1 = 0 (a + 1) (a ^ 2-A + 1 + 3a) + 1 = 0 (a + 1) ^ 3 = - 1A + 1 = - 1A = - 2 (a + 1) 2002 power + (a + 1) 2003 power plus (a + 1) 2004 = (- 1) ^ 2002 + (- 1) ^ 2003 + (- 1) ^ 2004 = 1-1 + 1 = 1

(5x-1200) / (4x-1000) = 13:10
How to solve this equation?

（5X-1200）/（4X-1000）=13：10
10×（5X-1200） =13×（4X-1000）
50X-12000 =52X-13000
52X-50X =13000-12000
2X=1000
X=500

4/X=3.6：1.2

4 / x = 3.6:1.2, i.e. 4 / x = 3
So x = 4 / 3

Given the function f (x) = | x2-4x + 3 |, (1) find the monotone increasing interval of the function; (2) find the value range of M, so that the equation f (x) = MX has four unequal real roots
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(1) Because the symmetry axis of y = x2-4x + 3 is x = 2, and the intersection point with X axis is (1,0), (3,0), the monotone increasing intervals of F (x) = = | x2-4x + 3 | are (1,2) and (3, + infinity) (2) in order for the equation f (x) = MX to have four unequal real roots, it is necessary that the image of F (x) = | x2-4x + 3 | and the image of y = MX have four

What's the difference between "CE" and "C" of calculator?

CE is the abbreviation of clear enter, which means to clear the input. When you type a number, press the corresponding number key. If you press wrong, you can use the (CE) key to cancel the value once, and then re-enter the correct number. If you press 18 + 9, and then press CE, you will clear the last input 9. At this time, you can change it to 10, and the result is 18 + 10 = 28
In addition to the above CE functions, C can also clear the contents on the display
The most obvious difference is that when you calculate a result, if you press CE, there will be no change on the display, and press C to clear it


In the formula r = (r1r2) / (R1 + R2), if R and R2 are known and R is not equal to R2, then R1 =?

R1R2=R(R1+R2) R1R2=RR1+RR2 R1R2-RR1=RR2 R1(R2-R)=RR2 R1=RR2/(R2-R)
Step by step, R1 = RR2 / (r2-r) is the final answer