Math Problems I can t do it, math can t do it, ask for a solution

3^x+3^y

2*Root number (3 x*3 y).

2*Root number (3*(x+y)).

2*Root number (3 5).

18 root No. 3

Using the mean inequality a+b 2 * root number ab(a,b 0)3x+3y 2 * root number 3 (x+y), because x+y=5, the fifth power of the original equation 2*3 opens the root number.

Because the exponential power can't be played, just read it. Will just die and forget to take and other conditions.

Don't forget, do the questions in the future, x=y=time, etc.

The easiest way:

x=0, y=5 and x=5, y=0, the result is 244x=1, y=4 and x=4, y=1, the result is 84x=2, y=3 and x=3, y=2, the result is 36 other methods are troublesome.

I'm not as smart as the people above, I use the stupidest method, find out all the values of y, x in the calculation, I calculate it is 35, I don't know if it's right, hehe.

Comprehension, doing questions is to deepen understanding, and science things are done.

284 ？I haven't done it for a long time, and I kind of forgot that it should be a very simple question.

Original = 3 x + 3 (5-x) > = 2 * under the root number (3 x * 3 5-x) = 18 * root number 3

x=y=.

Apply the mean theorem once.

The first year, 30000

In the second year, 30,000 (1+10%)

In the third year, 30,000 (1+10%) 2 (the small tip is squared) and so on, in the fortieth year, 30,000 (1+10%) 39 and then add, 30,000 (1+10%)+

Solution: The first profit.

60-60 (1+20%)=10 (RMB).

The second is a loss.

60 (1-20%)-60=15 (yuan).

A total loss of 15-10=5 (yuan).

The cost price is. 420 ((1+50%)).

Question 3. The cost of making money is 60 (1+20%)=60 yuan), the cost of losing money is 60 (1-20%)=60 yuan), and the total cost is 50+75=125 (yuan).

So the loss is 125-60x2=5 (yuan).

Question 4. Now the selling price is the cost (1+50%)x90%=the cost is 420 (yuan).

Because the area expression he got earlier is -x squared + (l 2)x, this is a quadratic function about x, then when x = a quarter l, this quadratic function obtains the maximum value, if you don't understand, you can check the maximum value of the quadratic function.

Solution: Let one side be x, then the other side is (l-2x) 2-2-l-2-x, s2x(l 2-x) and x-tenl2-x-2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2x2l2l2x2l2l2x2l2l2x2l2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2l2x2x2l2x2l2x2l2x2l2x2l2x2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2l2

It's best to ask the teacher, if it's a holiday, you can help yourself through homework help or little ape search questions.

Through the expression of the function s3, it can be concluded that the function image opening is downward, and there is a maximum value at the symmetry axis of the function, and the symmetry axis of the function is x=b (-2a), and substituting it to obtain x=(-l 2) (2), we can calculate x=l 4, that is, the function is at x=l 4, and the maximum value is taken.

Set the red Heng Cheng persimmon has x kilograms.

x-250）/x=1/6

Solution x=300

Tomatoes and cucumbers are transported to 250 + 300 = 550 kg.

f(x1+x2)=0.Solution: From the known analytic expression of the quadratic function, it can be seen that no matter whether the opening is up or down, it must pass through (0,0) and (-b a,0), so it is easy to know that x1+x2=-b a, so that f(x1+x2)=f(-b a)=0

You wrote it so succinctly, I thought it was a physics problem.

It should be a physics problem, right?

The absolute value of the change in velocity over the two time periods is equal: a t1 = a' t2 = a'(t - t1)

Solution: t1 = a' t/(a+a'), where t = t1+t2

From a mathematical point of view, the results can be written directly with an inverse relationship.

Straightforward solution: Because a t = constantTime is inversely proportional to a:

t1 = t (1/a)/[(1/a + 1/a')] = a' t/(a+a'),

Is it an angular bisector? If so, change the left side of the first step to t2:t1.

Does the title mean to go from A to B and back to A, is T the time and A the speed? Because the distances are equal, and s at,a is inversely proportional to t, it is easy to derive the listed formula.

T1 is known to be t2 = a'：a……①

t1+t2=t......②

is brought in by t2=t total -t1

t1 (t total -t1) = a'/a

a×t1=a'(t-total-t1).

a×t1+a'×t1=a't total.

t1=a'Mr. Special (Ah + Ah')