120 divided by x minus 60 is one-third,

120 divided by x minus 60 is one-third,

（x-60）=3X120,
x-60=360,
x=420

If the two roots of the quadratic equation 2x ^ 2 + 4x-1 = 0 are X1 and X2, then 1 / X1 + 1 / x2 =?
1. If the two roots of the equation 2x & # 178; + 4x-1 = 0 are x1, then 1 / X1 + 1 / x2 =?
2. The real root of equation 1 / 4-x & # 178; + 2 = - 1 / 4 (X-2) is?
The + 2 of the second question is a separate item

Let's use Veda's theorem (the relationship between root and coefficient) to do this, where a = 2, B = 4, C = - 1, then X1 * x2 = C / a = - 1 / 2, X1 + x2 = - B / a = - 2 to divide the original formula, and get (x1 + x2) / x1x2 = 42

12 calculate (1) the square of three thirds of X - (- the square of one-half of x) + (- the square of 2x) (2) (- the square of 9x - 3 + 2x) + (- the square of X-5 + 2x)

(1) 3 / 2 x squared - (- 1 / 2 x squared) + - 2x squared
=1.5x^2+0.5x^2-2x^2
=0
(2) (- 9x's Square - 3 + 2x) + (- X-5 + 2x's Square)
=-9x^2-3+2x-x-5+2x^2
=-7x^2+x-8
It's done

Using the square difference formula: (1) (2x-7) &# 178; (2) (2x + 1 / 2Y) &# 178; (3) (A & # 178; + 1) &# 178; (4) 1001 & # 178;

（1）(2x-7)²
=（2x)²-2×2x×7+7²
=4x²-28x+49
(2)(2x+ 1/2y)²
=(2x)²+2×2x×1/2y+(1/2y)²
=4x²+2xy+1/4y²
（3）（a²+1）²
=(a²)²+2a²+1
=a^4+2a²+1
（4）1001²
=(1000+1)²
=1000²+2×1000×1+1
=1000000+2000+1
=1002001

Mr. Zhang will take the students to Beijing during the summer vacation. Travel agency a says that if the principal buys a full ticket, the rest of the students can enjoy half price discount. Travel agency B says that all the students including the principal will enjoy a 60% discount on the full ticket price (60% of the full ticket price, and the full ticket price is 240 yuan)
How many students do the two travel agencies charge the same?
If there are three or five students, how much does it cost to add the travel agency?

There are X students
240+120x=240×0.6（X+1)
The solution is x = 4
A: there are four students

In higher mathematics, (x, y) tends to (0,0) LIM (x ^ 2-y ^ 2) / (x ^ 2 + y ^ 2)

Let y = KX (k is not equal to 0), then LIM (x - > 0, Y - > 0) [(X & sup2; - Y & sup2;) / (X & sup2; + Y & sup2;)] = LIM (x - > 0, Y - > 0) [(X & sup2; - KX & sup2;) / (X & sup2; + K & sup2; X & sup2;) = LIM (x - > 0, Y - > 0) [(1-k & sup2;) / (1 + K & sup2;)
∵ for different values of K, the upper limit has different values
Its limit does not exist

If the definition field of function y = x ^ 2-3x-4 is [0, M],

The original function is y = (M-3 / 2) ^ 2-25 / 4;
The classification of M is discussed: if M 3 / 2 and y get the minimum value at x = 3 / 2, y = - 25 / 4

You are the only one in my heart without him
You are the only in my heart

My heart is only you and without him

How many hectares is 10000 mu?

1 ha = 15 mu, 10000 mu is 10000 / 15 = 666.67 ha

Decomposition factor: the product of the 2m power of half a + the m power of a and the m power of B + the 2m power of half B

The original formula is: 1 / 2A ^ 2m + A ^ MB ^ m + 1 / 2B ^ 2m
=1／2(a^2m＋2a^mb^m＋b^2m)
=1／2[(a^m)²＋2a^mb^m＋(b^m)²]
=1／2(a^m＋b^m)²
Principle: A & # 178; + 2Ab + B & # 178; = (a + b) &# 178;