Simple math problems in the first year of junior high school, the master will come to the master, an

Let the import volume of the previous month be x, ** is y, and the growth rate is a%, xy(1+14%)=x(1-5%)y(1+a%)xy, which can be approximated, and it becomes a one-dimensional equation about a.

114=95+95a%

Solution a%=20%.

ps: International oil prices have plummeted recently. ）

Upstairs don't want to think about it, if the price of oil rises so much, may the whole cost rise by 14%?

The first floor copied the wrong data when calculating the "cost of the month", and the second and third floors simply misunderstood the relationship between import volume, oil price and import fees.

And the question of the growth rate cannot be calculated according to them.

If the import volume of the previous month is x, ** is y, then it is now , and, so it has increased.

Assuming that its oil imports in the previous month were A, oil ** was B, and the growth rate of oil ** in this month relative to the previous month was x, then.

a(1-5%)*b(1+x)=ab(1+14%), x=

That is, the growth rate of oil ** this month is 20% compared to the previous month

Suppose the import volume of the previous month is a, the oil ** is b, and the growth rate of ** is x, then there is: (1-5%) a*(1+x)b=(1+14%)abx=, that is, 20%.

Set the price of oil **x

If the oil price of the previous month is 1, then the current month is 1*(1+x).

If the import volume of the previous month is 1, then the current month is 1*(1-5%), the last month's fee is 1*1, and this month's is 1*(1+x)*1*(1+5%), and the fee increases by 14%.

So 1*(1+x)*1*(1+5%)=1*1*(1+14%)1+x=114 105

x=9 105=3 35 is approximately equal to.

So the oil plus rises.

Solution: Set x of a species and y of b species.

90x<3600 x<40

100y<2900 y<29

x+y=50

There are 19 types in total.

The square root of is 4

2x-1=16

The arithmetic square root of 4x+y-2 is 6

4x+y-2=36

x=17/2 y=4

2x-5y+19=16

The square root of 16 is 4

2.Root number 7 is more than 2 o'clock.

So 5 + root number 7 = 7 + x

5 - root number 7 = 2 + y

The above formula plus the lower formula gives 10=9+x+y

So x+y=1

3.The number under the following sign must be greater than or equal to 0

x-2>=0 2-x>=0

x=2y=3

So the x times of y is 9

The square root of 9 is 3

1.Because the square root of 2x-1 is 4

So 2x-1=16, x=17 2

Because the arithmetic square root of 4x+y-2 is 6

So 4x+y-2=36, y=4

So, 2x-5y+19=2*17 2-4*5+17=162The question should be wrong, it should be 5 + the integer part of the root number 7 is x, the whole part of the root number 7 is 2

So the decimal part of x=7 is 7-2

So y = root number 7-2

So x+y=7 + root number 7-2=5 + root number 7

3.According to the non-negativity of the square root, it can be known that:

x-2 0 so x2

2-x 0 so x 2

So x=2, so y=0+0+3=3

So y to the x-power = 3 to the 2nd power = 9

Solve inequality 1.

x is any number of rounds of reeds.

Solve inequality 2.

Negative seven-ninths of the search for the Tong faction "Sega x

So. Negative Seven Nineths x

Set the call time to x, then: y global pass = 30 + y quick pass =.

1) 30+ solution x 150, so when the talk time is greater than 150 minutes, it is cost-effective to get it all over the world.

2) 30+ solution x 150, so when the talk time is less than 150 minutes, it is quick and cost-effective.

Set the call time to x.

30+x=150 When the monthly airtime x = 150 minutes, the cost is the same (1) When the monthly airtime x > 150 minutes, select "Global Pass" (2) When the monthly airtime x < 150 minutes, select "Express" pass.

30+x=150

x 150, which means that when the call time is more than 150 minutes, it is more cost-effective to choose Global Pass, which is solved by 30+: x 150, which means that it is more cost-effective to choose Quick Pass when the call time is less than 150 minutes

Column equation: 30+

Get: 30=x=150

Therefore, if it is less than 150 minutes per month, it is cost-effective to use Express, and if it is more than 150 minutes, it is cost-effective to use Global Pass.

From the following equation of the problem: 30+, the solution: x=150 is the same price of the two choices, and the solution is 30+, and the solution:

x 150, which means that when the call time is more than 150 minutes, it is more cost-effective to choose Global Pass, which is solved by 30+: x 150, which means that it is more cost-effective to choose Quick Pass when the call time is less than 150 minutes

Time is x

Solution: Set up 30+ fast passes for global passes.

1) Global cost-effective: 30+

x 150 when x 150 is fully cost-effective.

2) Quick and cost-effective: 30+

x 150 when x 150 fast cost-effective...

1) Set a reduction of x yuan, the original tourist is y person (y can be offset by kaiqing) original income: 60y

After the price reduction, the stool was confiscated:

According to the title: that is: solution: x = 10 yuan.

2) Shopping mall A shopping more than X yuan.

Gotcha: Keep an eye on it.

Solution x 150 yuan.

Note: X should never be equal to $150, which is off-topic.

Question 1: Method 1: (direct calculation) 199 + 201 + 197 + 203 + 200 + 195 + 197 + 199 + 203 + 206 = 2000 kg Method 2:

Using positive and negative numbers to calculate, more than 200 kg is recorded as positive, less than 200 kg is recorded as negative, then: -1 + 1 + (-3) + 3 + 0 + (-5) + (3) + (1) + 3 + 6 = 0 kg so (200 + 0) x10 = 2000 kg 2 question (1) 1 + (-2) + (3) + 4 + 5 + (-6) + (7) + 8 + (-9) + 10 + (-11) + 12 = 0(2) At least 4 such negative signs need to be added, such as 1+2+3+4+5+(-6)+7+8+9+(-10)+(11)+(12)=0

de bc, by the inside angles equal, e= 2 = 1, and by the triangle the inner angles and 180 degrees, e=35 degrees.

Because de bc d = 110°

So dbc=180°-110°=70°

Because 1= 2

So 1=70°*1 2=35°

Because the inner degree of the triangle is 180°

So e=180°-110°-35°=35°

……Are you in elementary school prep?

Because de parallel bc

The angle d is equal to 110°

Angle 1 is equal to angle 2

And because angle 2 is equal to angle e, I don't need to say the reason, right?

So the angle e is 35°