Solution equation: 120 / (X-60) = one third, 15x - (x-3) = 13

Solution equation: 120 / (X-60) = one third, 15x - (x-3) = 13

120 / (X-60) = one third
x/3=120+20
x=420
15x-(x-3)=13
15x-x+3=13
14x=10
x=5/7

The solution equation is 0.55 * (1-x) + 0.35 * x = 0.52

0.55*(1-x)+0.35*x=0.52
55*(1-x)+35*x=52
55-55x+35x=52
-20x=-3
x=3/20

In the equation of 1 + 2 + + 3 = 150, only one firestick can be moved. How can I make 1 + 2 + 3 equal to 150

1+2+3=150
The match below 2 moves to + after 1 and becomes 4
Two becomes seven
Then 147 + 3 = 150

If the equation | x ^ 2-2x | = m has two unequal real roots, then the value range of M is
It's the process```````

When m = 0, X & sup2; - 2x = 0 obviously has two unequal real roots 0 and 2. When m > 0, | x ^ 2-2x | = m is equivalent to the following two equations: ① x ∈ [0,2], X & sup2; - 2x + M = 0, ② x ∈ (- ∞, 0) ∪ (2, + ∞), X & sup2; - 2x-m = 0

In the plane rectangular coordinate system, the coordinates of points a and B are (10,0), (2,4) respectively. (1) if point C is the symmetric point of point B about X axis, find the path o
In the plane rectangular coordinate system, the coordinates of points a and B are (10,0), (2,4) respectively
(1) If point C is the symmetric point of point B about the x-axis, find the analytical formula of the parabola passing through O, C and a;
(2) If P is a point on a parabola different from C, and △ OAP is a right triangle, write the coordinates of point P directly;
（1）∵B（2,4）,
∴C（2,-4）；
Let y = ax (X-10) be the analytical formula of parabola passing through O, C and a
Substituting C (2, - 4) into,
A =;
Therefore, the analytical formula of parabola is y = -;
(2) P (8, - 4)
What I want to ask is, how did this point (8, - 4) come from?
I also know that if points o, P and a are on the same semicircle, and the center of the circle is I [5,0], the radius is 5, and the perpendicularity is Q, then the square of IP = the square of PQ + the square of IQ. Because point P is on a parabola, we can set the coordinates of point P as (m, 1 / 4m ^ 2-5 / 2m). Unfortunately, we will get a quartic equation,

The first question is: ∵ C is the symmetric point of point B about X axis, and B (2,4), ∵ C (2, - 4);
According to the parabolic equation y = x (AX + b) + C, y = x (1 / 4x-5 / 2) is obtained by taking a, O and C into three points
Sorry, I can't square it, so I wrote it separately
The second question is that O, P and a are on the same circle. The standard equation of the circle is x ^ 2 + y ^ 2 + DX + ey + F = 0 (that's Square, not 2)
And because P is a point on the parabola different from C, and △ OAP is a right triangle, so C is also on the circle
X ^ 2 + y ^ 2-10x = 0 brought in according to the three points of C / O / A
At the intersection with the parabola in question 1, y = - 4, x = 2 or 8 ∵ (2, - 4) is the coordinate of point C, and P is not C according to the meaning of the title
∴P（8,-4）；
Ah, it's not easy to find the parabola and circle formula after forgetting Baidu's formula for a long time. If the landlord has points, he can add some points

Simple calculation of 99 × 15

99×15
=（100-1）×15
=100×15-1×15
=1500-15
=1485

200＋10x＝150＋20x

200＋10x＝150＋20x
20x-10x=200-150
10x=50
x=5

In a given ellipse, if the chord length passing through the focus and perpendicular to the major axis is 2 and the distance from the focus to the corresponding guide line is 1, then the eccentricity of the ellipse is 0______ ．

Let the elliptic equation be x2a2 + y2b2 = 1 (a > b > 0), then there is 2b2a = 2 and a2c-c = 1, and then E = 22 can be obtained by dividing the two equations

1 + 7-13 = 44 how to move a match to make the formula hold?

Take the + of 1 + 7 here to the 1 of - 13
It's like this:
117-73=44
The equation holds

The solution (20 + 2x) (40-x) = 1200 needs detailed process

（20+2x)(40-X）=1200
800-20x+80x-2x²-1200=0
2x²-60x+400=0
x²-30x+200=0
（x-10）（x-20）=0
X-10 = 0 or x-20 = 0
x1=10 x2=20