Xiao Ming's glass balls are four times as big as Xiao Gang's. Xiao Ming gives Xiao Gang three, and they have the same number. How many glass balls do they have

Xiao Ming's glass balls are four times as big as Xiao Gang's. Xiao Ming gives Xiao Gang three, and they have the same number. How many glass balls do they have

Let Xiaogang x, then Xiaoming has 4x. After Xiaoming gives Xiaogang 3, Xiaoming has 4x-3 left, and Xiaogang has x + 3. If two people are equal, then x + 3 = 4x-3, and the solution is x = 2, so Xiaogang has 2 balls and Xiaoming has 4 * 2 = 8 balls

Xiao Gang made 16 shots and hit 15; Xiao Ming made 20 and hit 18. What's their shooting percentage?

Xiao Gang: (15 △ 16) × 100% = 93% (approximate value)
Xiao Ming: (18 △ 20) × 100% = 90%

What is the integral of the negative x power of E from negative infinity to positive infinity?

Positive infinity

Let E1 and E2 be non-zero vectors which are not collinear, and a = e1-2e2, B = E1 + 3e2 (1) prove that a and B can be a set of bases
2) Decomposing vector C = 3e1-e2 with a and B

1A and B can be used as the basement, that is, a, B can be the basement, that is, a, B is the non-zero vector of the non collinear line, that is, a, B is the non-zero vector of the non collinline, that is, a, B is the non-zero vector of the non collinline, that is, a, B is the non-zero vector of the non collinline, that is, a, B is the non-zero vector of the non collinline, that is, a, a, B is the non-zero zero vector of the non collinline of the non collinline, that is the non-zero zero vector of the non collinear line, that is the non-zero zero zero vector of the non collinline, that is the non-zero zero zero vector of the non collinline, that is the non-zero vector of the non collinline, that is the non-zero zero vector of the non collinline, that is the non-zero vector of the non-zero vector of the non collinline, that is the non-zero vector of the non-zero if a and B are nonzero vectors, i.e. a = KB, i.e. e1-2e2 = K (E1 + 3E

Solve the linear equation of three variables! 2x + 3Y + 4Z = 9 3x + 5y-2z = 11 5x + 7y-6z = 13

2x+3y+4z=9 ①
3x+5y-2z=11 ②
5x+7y-6z=13 ③
3 * ① - 2 * ② get - y + 16Z = 5 ④
5 * ① - 2 * ③ is y + 32z = 19 ⑤
-④ The result is - 48Z = - 24, z = 1 / 2
Substituting Z into 4 gives y = 3
Substituting y and Z into 1, we get x = - 1
So x = - 1, y = 3, z = 1 / 2
o(∩_ ∩)o

0.5x + 3 / 4 = 3 / 4 to solve the equation

0.5x+3/4=3/4 0.5x=0 x=0

In order to find the solution of the system of inequality equations, the specific process is 3x & sup2; - 4x-5 > 0, X & sup2; - x + 1 < 0

3X²－4X－5＞0 --------1)
X²－X＋1＜0----------2)
From 2) we get the following results
(x-1/2)²+3/4

How much is arctan (1 / 2)?
What is arc?

Arc is the inverse operation of trigonometric function. If sin (30 degrees) = 1 / 2, then arcsin (1 / 2) = 30 degrees
Similar to arcsin, arccos, arctan, arccot
So arctan (1 / 2) = 0.463648 = 26.5651 degrees

On the roots of the equation (BX) &# 178; - 1 = 0 (B ≥ 0) of X

(bx)²-1=0
∴(bx)²=1
∴bx=±1
x=±1/b

In the expansion of (ax-1x) 8, the coefficient of X2 is 70, then the value of real number a is 70______ ．

The general term of (ax − LX) 8 expansion is tr + 1 = CR8 (AX) 8 − R (− LX) r = (− 1) ra8 − rcr8x8 − 3R2, let 8 − 3R2 = 2 get r = 4, so the coefficient of x2 term in the expansion is a4c84 = 70, and the solution is a = ± 1, so the answer is: a = ± 1