（1）6X^2-7x+1=0 （2）5x^2-18=9x (3)4x^2-3x=52 （4）5x^2=4-2x The method of collocation for quadratic equation of one variable,

（1）6X^2-7x+1=0 （2）5x^2-18=9x (3)4x^2-3x=52 （4）5x^2=4-2x The method of collocation for quadratic equation of one variable,

6X ^ 2-7x + 1 = 0 factoridecomposition (6x-1) (x-1) (x-1) = 0, 6x-1 = 0 or X-1 = 0 or X-1 = 0 = 1 / 6 or x = 15x ^ 2-9x-18 = 0 = 0, or x = 15x ^ 2-9x-18 = 0, x = 5x + 6 (6) (x-3) (x-3) = 05x + 6 = 0 or x-3 = 0 or x-3 = x-3 = 0 (X-6 / 5 or x = 34x ^ 2-3x-52 = 0 factor decomposition (4x + 13) (x-4) = 04x + 13 = 0 or x-4 = x-4 = x-4 = x = 13 / 4 or x = 4, the matching methods are very tired, 6x ^ 2-7x + 7 x + and

5(2-x)=-(2x-7) 0.5x-2=0.8(2x-1.5) 2(x+0.5)-3(x-0.4)=5.6

5(2-x)=-(2x-7) 0.5x-2=0.8(2x-1.5) 2(x+0.5)-3(x-0.4)=5.610-5x=-2x+7 0.5x-2=1.6x-1.2 2x+1-3x+1.2=5.6-5x+2x=7-10 0.5x-1.6x=-1.2+2 2x-3x=5.6-1-1.2-3x=-3 -1.1x=0.8 -x=3.4x=1 x=-8/11 x=-3.4

A * b = 2 × a + B calculation x * 2x * 3x * 4x * 5x * 6x * 7x * 8x * 9x = 3039x= 

x*2x=4x
4x*3x=11x
11x*4x=26x
26x*5x=57x
57x*6x=120x
120x*7x=247x
247x*8x=502x
502x*9x=1013x=3039
X=3

For any integer A.B, a * b = 2xa + B, if x * 2x * 3x * 4x * 5x * 6x * 7x * 8x * 9x = 3039, find the integer X fast

a*b=2xa+b
It can be seen that the first number is multiplied by two times, and the second number remains unchanged
The first X is multiplied eight times twice, 2x is multiplied seven times twice, 3x is multiplied six times twice, and so on, and so on, 9x does not change
x*2X*3x*4x*5x*6x*7x*8x*9x
=x*2^8+2x*2^7+3x*2^6+...+8x*2+9x
=x*(256+256+192+128+80+48+28+16+9)
=1013x=3039
=>x=3

Using formula method to solve: (1) 6x ^ 2-7x + 1 = 0 (2) 5x ^ 2-18 = 9x (3) 4x ^ 2-3x = 52 (4) 5x ^ 2 = 4-2x, solve with formula method!

（1）6X^2-7x+1=0
6X^2-7x=-1
X^2-7x/6=-1/6
X^2-7x/6+49/144=49/144-24/144
(x-7/12)^2=25/144
x-7/12=±5/12
x=7/12±5/12
x=(7±5)/12
（2）5x^2-18=9x
5x^2-9x=18
x^2-9x/5=18/5
x^2-9x/5+81/100=360/100+81/100
(x-9/10)^2=441/100
x-9/10=±21/10
x=9/10±21/10
x=(9±21)/10
(3)4x^2-3x=52
x^2-3x/4=13
x^2-3x/4+9/64=832/64+9/64
(x-3/8)^2=841/64
x-3/8=±29/8
x=3/8±29/8
x=(3±29)/8
（4）5x^2=4-2x
5x^2+2x=4
x^2+2x/5=4/5
x^2+2x/5+1/25=20/25+1/25
(x+1/5)^2=21/25
x+1/5=±√21/5
x=±√21/5-1/5
x=(±√21-1)/5

1x() + 2x() + 3x() + 4x() + 5x() + 6x() + 7x() + 8x() plus 9x() + 10x() = 1980

It's 37
Because:
If they are all the same numbers, they can merge similar items
[]{10+1}*5=1980
So it's 37~

First, simplify and then evaluate, (3x + 2) (3x-2) - 5x (x-1) - (2x-1) 2, where x = − 1 3．

Original formula = 9x2-4 - (5x2-5x) - (4x2-4x + 1)
=9x2-4-5x2+5x-4x2+4x-1
=9x-5，
When x = 1
At 3:00,
The original formula = 9x − 5 = 9 × (− 1)
3)−5=-3-5=-8．

5x-3 (2x + 1) = 6x-4 (5-3x) find x

5x-3 (2x + 1) = 6x-4 (5-3x) find x
5x-6x-3=6x-20+12x
20-3=6x+12x-5x+6x
19x=17
x=17/19

First, simplify and then evaluate, (3x + 2) (3x-2) - 5x (x-1) - (2x-1) 2, where x = − 1 3．

Original formula = 9x2-4 - (5x2-5x) - (4x2-4x + 1)
=9x2-4-5x2+5x-4x2+4x-1
=9x-5，
When x = 1
At 3:00,
The original formula = 9x − 5 = 9 × (− 1)
3)−5=-3-5=-8．

(3x + 2) (3x-2) - 5x (x-1) - (2x-1), x = one third

The original formula = (9x? - 4) - (5x? - 5x) - (4x? - 4x + 1)
=9x²-4-5x²+5x-4x²+4x-1
=9x-5
=9×1/3-5
=-2