Ask for answers! 8th Grade Math, Math Problems! Eighth grade

I'll help you, but I've been out of school for many years. The formula can't be listed, but I can remind you.

You can measure the angle of abc to find out.

The area of comparison is actually the ratio of the three sides.

Solution 1:

Let x +ax +bx-16=(x-1)(x-2)(x +mx+n) to finish.

x⁴+ax³+bx-16

x-1)(x-2)(x²+mx+n)

x^2-3x+2)(x^2+mx+n)=x^4+(m-3)x^3+(n-3m+2)x^2+(2m-3n)x+2n

Compare the coefficients, a=m-3, n-3m+2=0

b=2m-3n

2n=-16

The solution yields n=-8, m=-2, a=-5, b=20, so a=-5, b=20

Solution 2: Let x +ax +bx-16=a(x-1)(x-2), a is an integer, and when x=1, 1+a+b-16=0 is obtained

When x=2, we get 16+8a+2b-16=0, and we get a=-5 and b=20

The distance from A to B is 25 - 25 3 = , the average velocity is.

Don't overspeed. If you don't give a picture, how can you calculate it? I did my own calculations.

Solution: (1) From the image, it can be seen that the function image passes through the points (2009, 24) and (2011, 26).

Let the analytic formula of the function be: y=kx+b, 2009k+b=24

2011k+b=26

Solution: k=1

b=-1985

The relationship between y and x is y=x 1985;

2) Ling x = 2012, y = 2012 1985 = 27, the city's 2012 lychee planting area of 270,000 mu

Analysis: (1) According to the coordinates of the points through which the function image passes, the analytical formula of the function can be substituted into the analytical formula of the function and the analytical formula of the function can be obtained by using the method of undetermined coefficients;

2) Substituting 2012 into the analytic formula of the function obtained in the previous question, and the value of the independent variable can be obtained Comments: This question examines the application of primary functions, and the key to solving such problems is to sort out the primary function model from the practical problems, and use the knowledge of primary functions to solve practical problems

23.Set the angle bac = x degrees.

Angular CBE = Angular BAC + Angular C

Angle 3 = 31 + x 2 Angle 2 = x 2 Angle 4 = 118-x angle 3 + angle 4 + angle 2 + angle d = 180 The solved angle d = 31 degrees.

Piece. b+c>a=8 and abc are positive integers.

b can take 7 6 5

When b takes 7, c can be 6 5 4 3 2

When b = 6, c can be 5 4 3

When b = 5, c can take 4