Xiao Wang has 45 pieces with 10 yuan face value and 5 yuan face value, totaling 325 yuan, of which 5 yuan has () pieces

Xiao Wang has 45 pieces with 10 yuan face value and 5 yuan face value, totaling 325 yuan, of which 5 yuan has () pieces

Let 10 yuan have X pieces, 5 yuan have y pieces,
Then x + y = 45;
10x+5y=325
The solution is x = 20, y = 25
That's 25 tickets for 5 yuan

There are 40 sheets of RMB 5 and RMB 10, which are 360 yuan in total. How many sheets of RMB 5 and RMB 10?

Set 5 yuan x sheets, 10 yuan 40-x sheets
5X+10(40-X)=360
5X+400-10X=360
5X=40
X=8
5 yuan, 8 sheets, 10 yuan, 32 sheets

(a1^2+a2^2+a3^2)(b1^2+b2^2+b3^2)>=(a1b1+a2b2+a3b3)^2

(A1 ^ 2 + A2 ^ 2 + a3 ^ 2) (B1 ^ 2 + B2 ^ 2 + B3 ^ 2) - (A1 ^ 2 + A2 ^ 2 + a3 ^ 2) (B1 ^ 2 + B2 ^ 2 + B3 ^ 2). If you multiply this equation and dissolve it, you will find that it is the sum of three formulas > = 0, so > = 0, so this equation holds

A parallelogram cuts a triangle along the line between the midpoint of one side and the vertex of the opposite side. The area of the trapezoid is () times that of the triangle
A parallelogram cuts a triangle along the line of the midpoint of one side and the vertex of the opposite side. The area of the trapezoid is () times of that of the triangle

A parallelogram cuts a triangle along the line between the midpoint of one side and the vertex of the opposite side. The area of the trapezoid is (3) times that of the triangle
4-1 = 3 times

Let f (x) = 1 + lgx, G (x) = x ^ 2, then the x value of 2F [g (x)] = g [f (x)] is
The answer is 10 ^ (1 + radical 2) and 10 ^ (1-radical 2)

If f (g (x)) = 1 + lgx & # 178; = 1 + 2lgx, G (f (x)) = (1 + lgx) & # 178; = (lgx) & # 178; + 2lgx + 1 and 2F (g (x)) = g (f (x)), then 2 (1 + 2lgx) = (lgx) & # 178; + 2lgx + 1 is reduced to (lgx) & # 178; - 2lgx-1 = 0, so lgx = 1 + √ 2, or lgx = 1 - √ 2, then x = 10 ^ (1 + √ 2), or x = 10 ^ (1 -

A snail climbs from the bottom of a dry well to the wellhead. He climbs 3 meters up in the daytime and 2 meters down at night. It is known that the well is 17 meters deep. How many days will the snail climb to the wellhead
We need formula and analysis

Days = (17-3) / (3-2) + 1 = 15 days

It is known that three real numbers a, B and C satisfy a + B + C = 0 and ABC = 1. It is proved that at least one of a, B and C is greater than 32

It is proved that: ∵ a + B + C = 0, ∵ a, B, C must have a positive number. Let C > 0, a + B = - C, ab = 1C. In this way, a and B can be regarded as two real roots of the equation x2 + CX + 1C = 0. △ = c2-4 × 1c ≥ 0, that is, C3 ≥ 4 > 278, ∵ C > 3278 = 32

A triangle and a parallelogram have the same base and area. The height of a parallelogram is 10 cm, so the height of a triangle should be () cm
A. 10B. 5C. 20

Let the height of the triangle be h, the height of the parallelogram be h, the area of the triangle = bottom × h × 12, the area of the parallelogram = bottom × h; bottom × h × 12 = bottom × h; then 12h = h, so the height of the triangle = 10 × 2 = 20 (CM); answer: the height of the triangle is 20 cm

Given that point P is a moving point on parabola x2 = 4Y, the projection of point P on straight line y + 1 = 0 is point m, and the coordinates of point a (4, 2), then the minimum value of | PA | + | PM | is ()
A. 17B. 13C. 3D. 2

According to the definition of parabola, | PM | = | PF |, so | PA | + | PM | = | PA | + | PF | ≥ | AF |, that is, when a, P and F are collinear, the minimum value is 42 + (2 − 1) 217, so a

Factorization 2a2-8a2
2A and 178; - 8a and 178; is this formula

=2（a²-4a²）
=2（a+4a）(a-4a)
That's right. Believe me, it's wrong downstairs