The number a is 9.5, which is 2.5 less than 40% of the number B

The number a is 9.5, which is 2.5 less than 40% of the number B

(9.5 + 2.5) △ 40%, = 12 × 52, = 30; answer: B number is 30

The number a is 26 more than 4 / 5 of the number B. the number a is 86. How much is the number B? We need to use the equation

I went! The number a is x, the number B is y, X-5 / 4, y = 26, x = 86, y = 75
All right! Give it to me!

What is 8A one (5a + 8) equal to?

3a-8

The campus is 240 meters long and 180 meters wide, while the paper for drawing the campus plan is only 3 decimeters long and 2 decimeters wide
A. 1：100B. 1：1500C. 1：1000D. 1：150

Because 240 m = 24000 cm, 180 m = 18000 cm, 3 decimeter = 30 cm, 2 decimeter = 20 cm, option a, 24000 × 1100 = 240 cm ＞ 30 cm, so it is not suitable; option B, 24000 × 11500 = 16 cm, 18000 × 11500 = 12 cm, so there are too many spare paper, so it is not suitable; option C, 24

How to write the beginning and end of the article "looking for a good teacher around me"! Fast, urgent!

Beginning: if parents taught us to take the first step in life, then teachers taught us to step on the first step in life
End: Thank you for never sneering at us. When we try, you always pay close attention. Even if the result is so insignificant, you always let us know that you have seen our achievements. It is you who let us know that life can be as light as a piece of paper, as deep as the sea, and as vast as the sky, And we have to make our own choices. Every problem, discovery and experience that you lead us through fascinates us and makes us see the twinkling of wisdom in the ocean of knowledge

The square of 2013 minus the square of 2013 minus the square of 2012,

2012
Square of 2013 - square of 2013-2012
=（2013-2012）（2013+2012）-2013
=2013+2012-2013
=2012

As shown in the figure: O is the center of the regular triangle ABC. Can you divide △ ABC into three equal parts by rotation? If you can, design a segmentation scheme and draw a schematic diagram. (at least three)

Scheme 1: connect OA, OB and OC, as shown in figure a; scheme 2: take any point D on the edge of AB, rotate D 120 ° and 240 ° around point O to get D1 and D2, connect OD, od1 and OD2, as shown in Figure B; scheme 3: connect od1od2 with the same curve, as shown in Figure C

Isosceles triangle is an axisymmetric figure, it must have only one axis of symmetry______ (judge right or wrong)

According to isosceles triangle includes isosceles triangle and equilateral triangle which only two sides are equal. So the symmetry axis of isosceles triangle should be one or three

If real numbers x, y and Z satisfy the condition 2x + 4y-z = 0, x-2y + 3Z = 1
(1) When x and y are both nonnegative real numbers, the value range of Z is obtained
(2) When x + Y > Z, find the value range of Z

（1）2/7

It is known that nonzero vectors a and B satisfy | B | = root 2 and (a-b) (a + b) = 1 / 4. Find | a | the angle between vectors a and B

From (a-b) * (a + b) = a ^ 2-B ^ 2 = a ^ 2-2 = 1 / 4, a ^ 2 = 2 + 1 / 4 = 9 / 4,
So | a | = 3 / 2
(there is no condition for finding the included angle, at least you need to know a * B. please check)