Simple calculation of 62.4 - 37.5 - 2.15

Simple calculation of 62.4 - 37.5 - 2.15

It's hard to calculate
62.4 - 37.5 - 2.15
=62.4-(37.5+2.15)
=62.4-39.65
=62.4-(40-0.35)
=62.4-40+0.35
=22.4+0.35
=22.75

If x = 2, y = - 1 and x = 1y = - 1 are two solutions of the equation MX + NY = 15, find the values of M and n
There is no mistake in this topic

2m-n=15 m-n=15
m=0 n=-15

Find the rules: 1 / 4, 4 / 9, 9 / 16, (), 25 / 36, 2 / 3, 1 / 2, 3 / 4, 9 / 16, 81 / 16

16/25
8/27

In order to solve the equation, we must go through the past two steps of denominator and term shift?
Let its solution be x = - 2

1/2x+2=-1+2
1/2x=-1
x=-2

Simple calculation: 1 + 2 / 1 + 4 / 1 + 8 / 1 +... + 64 / 1 + 128 / 1

Let a = 1 + 2 / 1 + 4 / 1 + 8 / 1 +... + 64 / 1 + 128 / 1, then the two sides multiply by 22a = 2 + 1 + 2 / 1 + 4 / 1 + 8 / 1 +... + 64 / 1, and the left side is 2a-a = a, and the middle of the right side is the same minus a = 2-128 / 1 and 128 / 127, so 1 + 2 / 1 + 4 / 1 + 8 / 1 +... + 64 / 1 + 128

The location relationship between circle C1: x ^ 2 + y ^ 2-4x-4 = 0 and circle C2: x ^ 2 + y ^ 2 + 6x + 10Y + 16 = 0 is circle C1 and circle C2
rt

Intersection

When calculating division, Xiao careless wrote divisor 65 as 56 quotient 13 and remainder 52. Is the correct quotient?
All right, there's a prize

Let the divisor be X
X=56*13+52
X=780
The correct quotient is 780 △ 65 = 12

In the triangle ABC, angle a = 70 ° angle B, the bisector of the outer angle of angle c intersects at point D, and angle BDC = --

Because angle a = 70 ° the sum of angle B and angle c is 110 ° so the sum of outer angles of angle B and angle c is 180 ° and 180-110 ° and 250 ° respectively. Because the bisector of outer angle of angle B and angle c intersects at point D, the sum of outer angles of angle B and angle c is 125 ° and the sum of outer angles of angle B and angle c is 180-125 ° and 55 ° respectively

5 + 10 + 15 + 20 + +195+200           （1+3+5+… +1999）-（2+4+6+… +1998）

（1）5+10+15+20+… +195+200           =5×（1+2+3+4+… +39+40）=5×[（40+1）×20]=5×820=4100（2）（1+3+5+… +1999）-（2+4+6+… +1998）=（1+1999）×1...

What does x = B (:, 1:7) mean in MATLAB

close allclear alla=newfis('fuzzf');f1=1;a=addvar(a,'input','e',[-3*f1,3*f1]);a=addmf(a,'input',1,'NB','zmf',[-3*f1,-1*f1]);a=addmf(a,'input',1,'NM','trimf',[-3*f1,-2*f1,0]);a=addmf(a,'input',1,'NS','...