Solving equation 90.5x + (45-x) * 92 = 91.2 * 45

Solving equation 90.5x + (45-x) * 92 = 91.2 * 45

90.5x+(45-x)*92=91.2*45
90.5x+45*92-92x=91.2*45
90.5x-92x=91.2*45-45*92
-1.5x=(91.2-92)*45
-1.5x=-0.8*45
x=0.8*30
x=24

Simplify the ratio and calculate the ratio: 26:

1. For a project, group A and group B will complete it in 12 days. After 8 days, group A will leave the construction site and group B will continue to complete it in 6 days. If group A and group B do it alone, how many days will it take to complete the whole project?
2. There are two water inlet pipes a and B in a pool. If only pipe a is opened, it will take 9 minutes to fill. If only pipe B is opened, it will only take 8 minutes to fill. Now open pipe a for 5 minutes, and the rest will be filled by pipe B. how many minutes will it take to fill the pool?
3. Party A and Party B complete a work at the same time. After four days of joint work, Party A can complete all tasks only after six days of independent work. Given that Party A completes 1 / 80 of the project every day more than Party B, how many days does it take for Party A and Party B to complete the work alone?

It takes X days for a to complete and y days for B to complete
12/x+12/y=1 ①
8/x+8/y+6/x=1 ②
14 / x + 8 / x = 1 (3)
① And (2) simultaneous equations
x=18
y=36
A: it takes 18 days for a and 36 days for B
According to the meaning of the question: the efficacy of a = 1 / 9, the efficacy of B = 1 / 8
It will take another X minutes to fill the tank
5/9+x/8=1
x=32/9
A: it will take 32 / 9 minutes to fill up the pool
Let a take X days and B take y days
4/x+4/y+6/x=1 ①
1/x-1/y=1/80 ②
10 / x + 4 / y = 1.3
② And (3) simultaneous equations
x=40/3
y=16
A: it takes 40 / 3 days for a and 16 days for B

If the solution of equation lnx-6 + 2x = 0 is x0, then the largest integer solution of inequality x ≤ x0 is ()
A. 1B. 2C. 3D. 4

∵ equation lnx-6 + 2x = 0, that is, equation LNX = 6-2x. Draw the images of two functions y = 6-2x, y = LNX respectively: from the graph, we can know the abscissa of the intersection of two function images, that is, the solution x0 ∈ (2, 3) of equation lnx-6 + 2X = 0

99 and 2 / 7 times (- 14)

99 2 / 7 × (- 14)
= 99 × （- 14）+ 2 / 7 × （- 14）
= -（100 - 1）× 14 - 2 × 2
= - 14 × 100 + 1 × 14 - 4
= - 1400 + 14 - 4
= - 1400 + 10
= - 1390

The parabola y = AX2 + BX + C intersects the x-axis at two points a and B, and intersects the y-axis at point C. It is known that the symmetry axis of the parabola is x = 1, B (3,0), C (0, - 3), (1) find the analytic expression of the quadratic function y = AX2 + BX + C; (2) whether there is a point P on the parabola symmetry axis, so that the difference between the point P and B and C is the largest? If it exists, calculate the coordinates of point p; if it does not exist, explain the reason; (3) if a straight line parallel to the x-axis intersects a parabola at two points m and N, and if a circle with diameter Mn is just tangent to the x-axis, calculate the radius of the circle

(1) Substituting C (0, - 3) into y = AX2 + BX + C, we get C = - 3. Substituting C = - 3, B (3,0) into y = AX2 + BX + C, we get 9A + 3B + C = 0. (1) ∵ the line x = 1 is the axis of symmetry, ∵ B2A = 1. (2) (2 points) substituting (2) into (1), we get a = 1, B = - 2

The price of a computer is 3200 yuan after 20% price reduction. How many computers can I buy now for the original 20 computers?

Original price = 3200 (1-20%) = 4000 yuan
Now = 4000 × 20 △ 3200 = 25 sets

The definition and range of X + 2 of function y = 5

This function is an exponential function with two units added in the X direction of y = 5. Obviously, the domain of definition is the same as the exponential function, which is r
And the domain is Y > 0, now Y > 2

Li Hong and Wang Jun set out at the same time from two places 840 meters apart. After meeting for seven minutes, Li Hong's speed was 55 meters per minute,

840 meters in 7 minutes. It means 840 / 7 = 120 meters per minute. Now Li Hong's speed is 55 meters per minute, which means Wang Jun's speed is 120-55 = 65 meters per minute. If we have to use the equation, we can assume that Wang Jun's speed is x, so we have the equation 840 / (x + 55) = 7. The steps to solve this equation are to multiply x + on both sides at the same time

A kind of color TV was first reduced by 20% and then by 5%. What's the price now?

(1-20%) × (1-5%), = 0.8 × 0.95, = 0.76, = 76%; a: the current price is only 76% of the original price