Math problems, thank you for helping to solve them, you need a process, thank you very much!!!

Set: The gold paper edge is x cm wide. Solution: (90-2x)(40-2x)=90 40 72%.

3600-180x-80x+4xsquare=2592 Shift: 4xsquare-260x+1008=0

Each term is divided by 4 to get: x squared -65x+252=0 Solved by the formula of a quadratic equation:

a=1 b=-65 c=252 x=-b bsquared-4ac 2ax=65 65 65-4 252 2x=65 2 x1=65+ 2=discarded).

x2 = 2 = 2 = centimeters) Answer: The width of the gold paper edge is centimeters.

Check: 90 40-(90, 2+.)

16 1592 (square centimeters).

Let the width of the edge of the gold paper be x, then.

90+2x）×2x+40×2x=90×40÷72%×28%4x²+260x-1400=0

x²+65x-350=0

x-5）（x+70）=0

x=5 or x=-70 (rounding).

A: The width of the gold paper edge is 5cm

Solution: The width of the edge of the gold paper is cm, according to the theme, get.

At the same time, 72 90+2 40+2 5000 move the constant term to the right, change the symbol 4 +260 1400 each item at the same time 4 4 4 + 260 4-1400 4 0 to solve 5 70 is not in line with the topic, discard

A: The width of the gold paper edge is 5cm

Let the width be a90+2a)(40+2a)=90 40 72%90+2a)(40+2a)=5000

45+a)(20+a)=1250

a²+65a+900=1250

a²+65a-350=0

a+70)(a-5)=0

a=-70 (rounding) or a=5

So the width is 5 cm.

Solution: Set the edge width of the gold paper to xcm

90+2x)(40+2x)=3600÷72％3600+260x+4x²=5000

4x²+260x-1400=0

x²+65x-350=0

x-5)(x+70)=0

x1 = 5 x2 = -70 (rounded).

A: ...5cm...

90 divided, the result is calculated by yourself... Anyway, your topic seems a little unclear...

According to the binomial theorem, the constant term = c(5,2) (x) 1 x) = - 10.

(1) Let y=kx+b because there is a relationship between y and x, and it can be seen that y and a uniform decrease with the uniform increase of x are a linear relationship between y and x.

Replace x=0 y=150; x=1,y=120 two points are substituted to get k=-30, b=150So y=-30+150

2) When the train arrives at C, the remaining fuel volume is 30 liters.

From (1) the fuel consumption of the train is 30 liters per hour, the train travels 60 kilometers per hour, and the time from C to D is t=12 60=hours.

The amount of residual oil is liters.

The distance between d and b is 360-60x4-12=108 km.

m 10 + 108-24 = 94 liters.

Your classmate is right, because 240 multiplied by five-sixths gives the tonnage of soybeans, and the tonnage of soybeans is three-quarters of flour, so the tonnage of flour multiplied by three-quarters = tonnage of soybeans, so the tonnage of soybeans is divided by three-quarters of the tonnage of flour.

Rice 240t

Soybeans = 240 * 6 5 = 200t = flour * (4 3) so: flour = 200 (4 3) =

Your classmate is right, your algorithm is wrong.

The subject is different, if the subject is given flour, it is three-quarters of the soybean, it is multiplied...

Isn't this multiplication? I wonder if the landlord doesn't want to count it himself?

Solution: 1) f(x)=|x+1|-|x-1|=> f(x)= { 2, (x<=-1)2x, (11)

2) Let f(m) = k

f(k)=f[f(m)]=f(1998)-7/2=2-7/2=-3/2

k in the range of (-1,1], and k = f(k) 2=-3 4=> f(m)=-3 4

m in the range of (-1,1], and m=f(m) 2=-3 8

Question 1: Prov: 16m +48m, m is a non-zero real number, the value of 16m +48m is always greater than 0, and the value is greater than 0, and there are always two different real roots.

Question 2: s abc 16

From the root finding formula: x = 3m or -2m

The m value is -4 under the cube root