The square of X + 7x + 6 = 0

The square of X + 7x + 6 = 0

x^2+7x+6 = 0
(x+1) (x+6) = 0
So x = - 6 or x = - 1

X square + 7x + 6 = 0

（x+6）（x+1）=0
X = - 6 or - 1

The square of X - 7x + 6 = 0
The quadratic equation of one variable is solved by formula method

Solution
△=b²-4ac=49-24=25
∴
x=(7+√25)/2=(7+5)/2=6
x=(7-√25)/2=(7-5)/2=1

Square of X + 7x = 0

Square of X + 7x = 0
x（x+7）=0
So x = 0
Or x + 7 = 0
x=-7
So the solution is x = 0 or x = - 7

Compare the size 3x square + 7x + 12 and - x square + 19x + 2

(3x & # 178; + 7x + 12) - (- X & # 178; + 19x + 2) = 4x & # 178; - 12x + 10 = 4 (x-3 / 2) & # 178; + 10-4 × (3 / 2) & # 178; = 4 (x-3 / 2) & # 178; + 1 because (x-3 / 2) & # 178; ≥ 0, so 4 (x-3 / 2) & # 178; + 1 ＞ 0, 3x & # 178; + 7x + 12 ＞ - X & # 178; + 19x + 2

① 2-1 = 3 ② 3-2 = 7... Calculate the value of 1 + 3 + 5 + 7 +... + 2005 + 2007 according to the above rule

3=2 2 -1 2 5=3 2 -2 2 7=4 2 -3 2 …… 2005 = 10032 - 10022 2007 = 10042 - 10032 add up these 1003 equations to get 3 + 5 + 7 + +2005 + 2007 = 1004 2 - 1 2 so 1 + 2 + 5 + 7 + +2005+2007=1004 2

The value process of finding (+ 1) + (- 2) + (+ 3) + (- 4) + (+ 5) + (- 6) + (- 7) +. + (+ 2005) + (- 2006) + (- 2007)
No mistake, not all the mantissa of 7 are treated like this

First calculate (+ 1) + (- 2) + (+ 3) + (- 4) + (+ 5) + (- 6) + (+ 7) +. + (+ 2005) + (- 2006) + (- 2007) = 1003x (- 1) + (- 2007) = - 3010
Finally minus (- 7) x2
-3010 - [（-7）x2 ] = -3010 +14 = -2996
I have this idea, don't you think

The square of 1 = 1, the square of 1 + 3 = 2, the square of 1 + 3 + 5 = 3, what is the equation corresponding to the nth lattice

1+3+…… +(2n-1) = the square of n

Is it possible to arrange the continuous natural numbers 1 to 1001 into a rectangle and frame 16 numbers, the sum of which is 1998 1991 2000 2080?
Impossible, please say the reason; possible, please write the maximum number and the minimum number. (one of the four answers) 4 * 4 square

Tip: let the number in the upper left corner of the box be x, then the other numbers in the box can be expressed as: x + 1, x + 2, x + 3, x + 7, x + 8, x + 9, x + 10, x + 14, x + 15, x + 16, x + 17, x + 21, x + 22, x + 23, x + 24 X + 24 = 1998 or 1999 or 2000 or 2001, that is 16x + 192 = 2000 or 2080

If you arrange the continuous natural numbers 1 to 140 into a rectangular array in the way of Figure 2, and then use a 2 × 3 rectangular box to make 6 numbers, you can make your box
Is the sum of the six numbers in the box 147? If yes, find the smallest number in the box; if not, explain the reason
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35
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No
1. Horizontal box, let the first number of the first row be x, the second number (x + 1), the third number (x + 2), the second row be (x + 7), (x + 8), (x + 9) successively, and (x + 1) + (x + 2) + (x + 3) + (x + 7) + (x + 8) + (x + 9) = 147
X = 20. There is no third column after 20
2, vertical frame, let the first number of the first row be x, the second number (x + 1), the second row be (x + 7), (x + 8), the third row be (x + 14), (x + 15), there are (x + 1) + (x + 2) + (x + 7) + (x + 8) + (x + 14) + (x + 15) = 147
X = 35 / 2 is a fraction