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0.5x+4.8=6.3 x=?
0.5x=1.5 x=3
It is known that the height of the cylinder is 5 decimeters. If the cylinder is divided into two equal halves vertically through the center of the bottom surface and the surface area is increased by 60 square decimeters, the volume of the cylinder is 5 decimeters______ Cubic decimeter
The radius of the bottom surface is: 60 △ 2 △ 5 △ 2 = 3 (decimeter), the volume of the cylinder is: 3.14 × 32 × 5 = 141.3 (cubic decimeter); answer: the volume of the cylinder is 141.3 cubic decimeter. So the answer is: 141.3
What is the sum of a number and 1 / 7 equal to 15% of 4 / 9
Don't solve the equation, just the formula
4/9×15%-1/7
=1/15-1/7
=-8/105
A: the number is - 8 / 105
1. Given | 2x-3 | = 1, find X
2. The positions of rational numbers a, B and C on the number axis are shown in the figure. Find | a-c | + | B-C | + | a + C | + | B + C |
My number axis is not very good, but it's about this
____ b___________________ c______ 0____________ a____________
I just learned it
1. X = 2 or x = 1
2. The original formula = a-c + C-B + A + c-b-c = 2a-2b
It should be
4 / 5 of a number is 6 less than 2 / 5 of 90. What's the number?
4/5x=90*2/5-6
x=75/2
If a / B is a rational number, define the new operation "*" a * b = 2Ab + 1, for example: {- 3} * 4 = 2 * 4 + 1 = 23, try to calculate: {1} 3 * {- 5} {2} {6 * {- 7} * {- 2}
｛1｝
3*｛-5｝
=2*3*(-5)+1
=-30+1
=-29
｛2｝
｛6*｛-7}｝*｛-2｝
=｛2*6*(-7)+1}*｛-2｝
=｛-84+1}*｛-2｝
=｛-83}*｛-2｝
=2*(-83)*(-2)+1
=332+1
=333
There are 42 fewer pear trees than apple trees in the orchard. Apple trees are three times as many as pear trees. How many apple trees and pear trees are there?
If x is set for pear tree, 3x is set for apple tree
3X-X=42
2X=42
X=21
21 + 42 = 63 (trees)
A: there are 63 apple trees and 21 pear trees
Given that a and B are positive integers and satisfy 2A + 3B = 15, then the value of the algebraic formula A ^ 2-AB + B ^ 2 is____
a. B is a positive integer,
And satisfy 2A + 3B = 15
A = 3, B = 3. Or a = 6, B = 1
A ^ 2-AB + B ^ 2 = 9 or 31
A primary school held a spring sports meeting. The teacher in class 1 of grade 6 gave the sports commissar 100 yuan to buy chocolate and mineral water in the supermarket. Each student in the class was required to buy at least one bottle of mineral water and each athlete was required to buy at least one piece of chocolate. If there were 26 students in the class and 24 participants in the competition, the unit price of chocolate and mineral water was 3 yuan and 1 yuan respectively, then how could the sports commissar buy chocolate and mineral water Yes______ Species
The amount of money that can be freely used by the sports committee members is: 100 - (3 × 24 + 1 × 26), = 100-98, = 2 (yuan). With this 2 yuan, he can only buy 0, 1, 2 bottles of mineral water, that is, there are three ways to buy; a: there are three ways for the sports committee members to buy chocolate and mineral water
X + 4Y + 5Z = 5 2x + 2Y + 4Z = 1 for x-8y-7z
x+4y+5z=5 ①
2x+2y+4z=1 ②
② X-8y-7z = - 13
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- 2. The distance between a and B is 360km. A car travels 160km from a to B in four hours. How many hours will it take to reach B?
- 3. The two passenger and freight cars leave from a and B at the same time. When they meet, the distance ratio of passenger and freight cars is 4:5 After the meeting, the freight car traveled 27 kilometers per hour more than before, and the passenger car still drove at the original speed, and finally arrived at the same time. It is known that the passenger car traveled for 10 hours, and the distance between a and B is calculated Ask to write the process, not too complicated and explain
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- 10. A rectangular tank 30 cm long and 22 cm wide has a water depth of 12 cm. After a stone is placed, the water depth is 19 cm. What is the volume of the stone?
- 11. It is known that the sum of the first n terms of the arithmetic sequence an is Sn, and satisfies A2 + A4 = 14, S7 = 70
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- 16. Bookstores bring in a kind of books, which sell 30% in the first day, and 120% in the second day. The second day sells 30 more than the first day. How many books do bookstores bring in? Step 1: 30% X120% = 36% Step 2: 36% - 30% = 6% Step 3: 30 △ 6% = 500 I just want to ask, the answer to this question is in the last step, why is it 30 ／ 6% instead of 6% ／ 30?
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