7.2x1.47 + 14.7x0.28 by simple method

7.2x1.47 + 14.7x0.28 by simple method

7.2x1.47+14.7x0.28
=（7.2+2.8）x1.47
=10x1.47
=14.7

A minus B, the difference is 1.5; a divided by B, the quotient is also 1.5. What are a and B?

a-b=1.5
The quotient of a divided by B is 1.5, which means that a is 1.5 times of B, that is, a = 1.5b
Then we use A-B, that is, 0.5 times of B is 1.50.5b = 1.5
b=3 a=4.5

3x+5=7-2x
the sooner the better!

3x+5=7-2x
3X+2X=7-5
5X=2
X=2/5
X=0.4
If you don't understand, you are welcome to ask,

It is calculated by a simple method,
4 2 1
－×4+－×2+－×16
5 5 5

4/5*4+2/5*2+1/5*16
=1/5*(16+4+16)
=1/5*36
=7.2

It is shown that the square of 257 - the square of 512 can be divided by 12

The 7th power of 25 - the 12th power of 5
=The 14th power of 5 - the 12th power of 5
=The 12th power of 5 × (the 2nd power of 5 - 1)
=The 11th power of 5 × 5 × 24
=The 11th power of 5 × 120
The 11th power of 5 × 120 △ 12 = the 11th power of 5 * 10
It can be proved that the 7th power of 25 minus the 12th power of 5 can be divisible by 12

1.8x(3x-2.5)-3.8x=1.54

5.4X--4.5--3.8X=1.54
1.6X=1.54+4.5
1.6X=6.04
X=6.04\1.6
x=3.775

How to calculate 50-49 + 48-47. - 1

Let's take two numbers as a group, and the sum of each group is 50-49 = 1
So there are 50 / 2 = 25 groups
So the sum is 25 × 1 = 25
50-49+48-47.-1
=（50-49）+（48-47）+.（2-1）
=1×25=1
I'm a teacher. Thank you

If there is only one common point between the straight line y = x + m and the curve y = √ (4-x ^ 2), find the value range of the real number M

The curve y = √ (4-x ^ 2) is the upper half of the circle x ^ 2 + y ^ 2 = 4,
When the line y = x + m passes its right end point (2,0), M = - 2;
When the line y = x + m is tangent to the arc, M / √ 2 = 2, M = 2 √ 2,
The value range of M is [- 2,2 √ 2]

Find the remainder of the product 653 * 735 * 839 divided by 17

402682245/17=23687190.15

Simple calculation of 7.8 × 6.9 + 1.2 × 6.9 + 6.9

(7.8+1.2)×6.9+6.9