Solve the equation. 1, 5x-15 = + 5 + x the second question, X △ 3 = 4.6 + 56 the third, 3.2x-4 × 14 = 40 the fourth, 36 △ (x + 4) = 4

Solve the equation. 1, 5x-15 = + 5 + x the second question, X △ 3 = 4.6 + 56 the third, 3.2x-4 × 14 = 40 the fourth, 36 △ (x + 4) = 4

1、5x-x=5+15
4x=20
X=5
2、x÷3=60.6
x=60.6×3
x=181.8
3、2x-28=40
2x=40+28
2x=68
x=68÷2
x=34
4、x+4=36÷4
x+4=9
x=9-4
X=5
X+（X+56）+5X/3=5/2（X+56）
x+5x/3=5(x+56)/2-(x+56)
8x/3=(x+56)(5/2-1)=3(x+56)/2
16x=9(x+56)=9x+9*56
7x=9*56
x=9*8=72
The quadratic function y = x & # 178; + 2x-7 is known
(1) When x = - 1, find the value of function one;
(2) When x takes what value, the value of function y is 8?
(1) When x = - 1
y=(-1)²+2×(-1)-7
=1-2-7
=-5
(2)x²+2x-7=8
x²+2x-15=0
(x-3)(x+5)=0
x1=3,x2=5
When x = 3 or x = - 5, the value of function y is 8
(1) When x = - 1, find the value of function one. - 8
(2) When x takes what value, the value of function y is 8? 3 or - 5
Given the position of ABC three numbers on the number axis as shown in Figure 1, try to simplify | A-B | - | B-C | + | C + a | + | B | - 2 | a |
Wei b _______ c___ 0_____ a______________ （1）
First look at the absolute value of each item after the size of the value
a＞0,b＜0,→ a-b＞0 → |a-b|=a-b
|b|＞|C|,b＜c＜0,→ b-c＜0,→ |b-c|=c-b
|a|＞|C|,c+a＞0 |c+a|=c+a
b＜0,|b|=-b
a＞0,|a|=a
be
|a-b|-|b-c|+|c+a|+|b|-2|a|
＝a-b-(c-b)+c+a-b-2a
=-b
If the solution of equation 2x + a = X-1 is x = 1, find the value of 3a-2
Minus 8
It is known that 6x2 minus XY minus 15y2 is equal to 0. Find the fraction 2x2 minus 3xy minus 3y2, X2 minus 2XY + 4y2
6x2-xy-15y2 = (2x + 3Y) (3x-5y) = 0, so x = - 3 / 2Y or x = 5 / 3Y
The quadratic function    - x is known;
If the intersection of the image of this function and the X axis is a and B, the vertex is C, and the area of △ ABC is (4 times the root sign 2), the function expression of this quadratic function is obtained
Analysis:
The intersection coordinates of the image of the function and the x-axis can be set as a (x1,0) and B (x2,0)
Then we can see that X1 and X2 are two different real roots of the equation 2x & # 178; - 4mx + M & # 178; = 0
According to Weida's theorem: X1 + x2 = 2m, X1 * x2 = M & # / 2
Then: ab = | x2-x1 | = radical [(x1 + x2) &# 178; - 4x1 * x2] = radical (4m & # 178; - 2m & # 178;) = radical 2 * | M|
The analytic formula of the function is: y = 2x & # 178; - 4mx + M & # 178; = 2 (X & # 178; - 2mx + M & # 178; - M & # 178;) + M & # 178; = 2 (x-m) &# 178; - M & # 178;);
Then the vertex C coordinates are (m, - M & # 178;)
The distance between point C and x-axis is d = M & # 178;
So: s △ ABC = (1 / 2) * D * AB = (1 / 2) * M & # 178; * radical 2 * | m | = 4 radical 2
That is: | m |, # 179; = 8
The solution is m = 2
So the analytic expression of the function is: y = 2x & # 178; - 8x + 4 or y = 2x & # 178; + 8x + 4
It is known that LAL = 3, LBL = 2, where B
∵|a|=3.∴a=±3
|B | = 2 and B ＜ 0, B = - 2
A + B = 1 or - 5
If B is less than 0, B = - 2
A + B = 1 or - 5
1 or - 5
If the solution of the equation 2x + a = X-1 about X is the value of X with the minimum value of formula / x + 4 / + 5, find the value of 3a-2
Why is the small value - 4?
/X + 4 / + 5 has a minimum, so / x + 4 / = 0
So x = - 4
Substituting into the equation, a = 3
3a-2=7
The minimum value of X in the formula / x + 4 / + 5 is - 4. Substituting it into the original equation, we get a = 3, so 3a-2 = 7
Let the formula / x + 4 / + 5 have the minimum x = - 4, so a = 3 3a-2 = 7
2X + a = X-1 to get x = - (a + 1)
The substitution formula / x + 4 / + 5 has the minimum value, that is, the minimum value of / x + 4 / is 0, x = - 4
So - (a + 1) = - 4, a = 3,
3a-2=3*3-2=7
Let X and y be two of the equations x2 + x-3 = 0, then what is x2-4y2 + 19,
Because X and y are two of the equations X & sup2; + x-3 = 0, then x & sup2; + x-3 = 0, Y & sup2; + Y-3 = 0; and X & sup3; - 4Y & sup2; + 19 = x (X & sup2; + x-3) - 4 (Y & sup2; + Y-3) - X & sup2; + 3x + 4Y + 7 = - (X & sup2; + x-3) + 4x + 4Y + 4