Math master answers, good people are rewarded!

One. 1. Column equation solution: y=(600-10x)*(40+x-30) can be simplified y=-10x 2+500x+60002, and the maximum profit is obtained when x=25.

For ymax = 12250 at this time the price of the school bag is 40 + 25 = 65 yuan 1 two. 1. It is known by the nature of the parabola: the apex of this parabola opening is c(0,4) so let the parabolic equation:

y=-ax 2+4 a>0 when x=4 y=0 so a=1 4 so y=-1 4x 2+42, because ac is perpendicular bc so cqe is a right angle so let aq qb=a b

So cqe area = 1 2 * a * root number 2 * b = root number 2 2 * ab "root number 2 2 .

Alas, it's so complicated on the computer.

Question 1: (1) y = (10 + x) (600-10x) = -10x + 500x + 6000

2) The profit of 10,000 yuan is not the maximum profit of the month.

y=-10x +500x+6000=-10(x-25) +12250, when x=25, the maximum profit y=12250 yuan, at this time the price of the schoolbag is 25+40=65 (yuan).

Question 2: Known conditions are incomplete.

On the second floor, who told you that C is the apex of the parabola?

1)y=(40+x-30)(600-10x)y=(10+x)(600-10x)

2) y=-10(x-25) 2+12250When y=25, the maximum value is 12250

1) One condition is missing, and a b. cannot be solved

Upstairs is right, the opening can go up, and you can go down.

The second question is not qualified enough to ask for an answer.

For example: (1) There are many answers to question that meet two conditions.

y=－1/4*x^2+4

y=1/2*x^2-3*x+4

y=x^2-5*x+4

y=-x 2+3*x+4, etc.

As long as the parabola y=a*x 2+b*x+c, b 2-4*a*c 0 in the parabola y=a*x 2+c is sufficient, and c=4, b 2-16*a0 is satisfied.

The second question is a condition, right???

I hate to see questions that are too long.

1、y=（10+x）*（600-10x）

Find the maximum, y=-10(x-25) 2+12250x=25 is the maximum, and y is 12250

2. I won't do it.

1.Solution: Let the original weight of apples in basket B be x kilograms, then basket A has 3x kilograms of apples 3x-30=x+30

3x-x=30+30

2x=60x=30

30*3=90 (kg).

90 + 30 = 120 (kg).

A: There were 120 kilograms of apples in the previous two baskets.

2 solution: Let A catch up with B in x minutes.

100x=80x+100

20x=100x=5

Answer: A can catch up with B after 5 minutes.

1.Solution: Let the original basket A be x kilograms, and the original basket B will be y kilograms.

Can be listed x=3y

1x-30=y+30

2 Since a certain 1, 2 can get x=90, y=30

2 solution: Let x minutes be 100x=80x+100x=5, that is, after 5 minutes, A can catch up with B.

A basket x, B basket y

x=3yx-30=y

x=45y=15

Because it is a 400-meter loop, and A is 100 meters in front of B, it can be seen as A is 300 meters behind B 100x-300=80x

x=15

The basket turned out to have apples x kilograms.

x-30=1/3x+30

x = 90x minutes A can catch up with B 100x-80x = 400-100x = 15

(84-33+5) (2 3) = 56 * (3 2) = 84 flowers.

84 * (4 7) + 3 = 51 flowers.

So what they said was right.

That's right, because the unmade safflower is 84-33=51 flowers.

The number of people who did not do what a said = 84 * 2 3-5 = 56-5 = 51 flowers.

The number of undone flowers that b said = 84 * 4 7 + 3 = 48 + 3 = 51 flowers.

So that's right.

A and B are both right, a total of 84 flowers, 33 have been made, and 51 have not been done.

a: 2 3 of the total is 84 * 2 3 is equal to 56, 56 less than 5 is 51 b: 4 7 of the total is 84 * 4 7 is equal to 3 more, that is, 51

2n+3+6-n=0

n+9=0n=-9

When n=(-9), the value of 2n+3 is the opposite of the value of 6-n.

Take advantage of the property of numbers that are opposites of each other, i.e., add to zero, and then work out the correct answer.

Let n be x

Then 2x+3+6-x=o (the sum of two numbers that are opposite to each other is 0) x+9=0

x=-9

1、m＞02、n＜0

3. When n=0, m is arbitrary.

y=3x+8

When x=0,y=8, i.e., the coordinates of the intersection point with the y-axis (0,8)When y=0,x=-8 3, i.e., the coordinates of the intersection point with the x-axis (-8 3,0).

=(x-1/2)^2

4. =(t-2)*(t-4)

3 = (4m+1n)*(2m+3n) process. Completely square 2, we get 9m 2 + 12 mn + 4n 2 - (m 2-2 mn + n 2) = 8 m 2 + 14 mn + 3n 2 = (4 m + 1n) * (2m + 3n).

1.In natural numbers, prime numbers are? What are the composite numbers?

Within 10: prime numbers are 2, 3, 5, 7;The composite numbers are 4, 6, 8, 92The product of two non-zero natural numbers must be a composite number (right?).

Correct 3There is also the natural number of factor 2 that must be a composite number (right?). Wrong, e.g. 2 is the prime number 1

What number is both odd and composite? 9

2.Multiply two different prime numbers, the product must be a 3-digit number, it contains a factor 2, and it contains a factor 5, the hundred place is the smallest prime number, and the ten place is the smallest odd number, this number is?

is the smallest of the 210 smallest consecutive prime numbers, and is ? What is the product?

Sum: 2+3+5=10

Volume: 2x3x5=30

1.A two-digit number, divided by 4, divided by 5, divided by 6 has no remainder, these two numbers are the smallest?

This problem is to find that the least common multiple of 4, 5, and 6 is 60