2(x-8)-0.7x+2=3.81

2(x-8)-0.7x+2=3.81

First pick, first answer

What is the remainder of 111.1 (1000 ones) divided by 7?

Every 6 ones, divided by 7, there is 0, and 1000 △ 6 = 166.4, so the remainder of this number divided by 7 = 1111 △ 7, 1111 △ 7 = 158.5, so the remainder = 5

Given that 1x-1y = 3, the value of the fraction 2x + 3xy-2yx-2xy-y is ()
A. 15B. -15C. 35D. -35

From 1 X-1 y = 3, we obtain Y-X = 3 XY, X-Y = - 3 XY, 2x + 3 XY-2 yx-2 xy-y = 2 (X-Y) + 3 XY (X-Y) - 2 xy = - 6 XY + 3 xy-3 XY-2 xy = - 3 XY-5 xy = 35

（111…… 11) What is the remainder of 1997 divided by 7?

Six ones, divide by seven
111111 divided by 7 = 15873
1997 divided by 5 = 395
I think the remainder of 7 is the same as that of 11 divided by 7
11 / 7 = 1 remainder 4
Answer 4

Known: 2x. X + 4x + y.y = 2xy-4, find the value of Y X

2x^2+4x+y^2-2xy+4=0
(x^2+4x+4)+(x^2-2xy+y^2)=0
(x+2)^2+(x-y)^2=0
So x = - 2, y = - 2

The 1993 digit 11 composed of 1993 ones The remainder of 1 divided by 7 is ()

111111 / 7 = 15873, six ones divided by seven have no remainder
In 1993 / 6 = 332, 11993, there are 332 groups, 111111 and 1
So 1 / 7 ends with 1

Given x > 1 / 2, Y > 2 and 2xy-4x-y-2 = 0, find the minimum value of 2x + Y-5

2xy-4x-y-2 = 0. = = = = > y (2x-1) = 4x + 2. = = = > y = (4x + 2) / (2x-1) = 2 + [4 / (2x-1)]. The equation z = 2x + Y-5 = - 2 + (2x-1) + [4 / (2x-1)] ≥ - 2 + 4 = 2. The equal sign is obtained only when x = 3 / 2, y = 4

111… 11 (1889 ones) divided by 7, the remainder is?

111111 mod 7 = 0 111111 * 10 ^ n (n is a natural number) is an integral multiple of seven. The remainder of 1889 divided by 6 is five, that is, the remainder of 1889 is 7 = 11111 / 7 = 1587.. 2. So the original formula is divided by 7, and the remainder is 2. Why don't there be repeated characters

Given that 1 / X-1 / y = 5, finding the value + 1 of 2x + 5xy-2y of x-2xy-y is + 1 after this fraction

1/x-1/y=5
(y-x)/xy=5
y-x=5xy
(2x+5xy-2y)/(x-2xy-y)+1
=[5xy+2(x-y)]/[(x-y)-2xy]+1
=-5xy/(-7xy)+1
=5/7+1
=12/7

111 ······· 111 (100 ones), this number divided by 7, the remainder is ()

The remainder is 5, which is analyzed as follows: 100 △ 6 = 16 According to the property of being divisible by 7, 111111 can be divisible by 7. It is proved that 111111.111-111 = 0 = 0 * 7 0. That is 16 segments 11111100 ...