Math problem: the square of Y2 is 4, what is y equal to?

Math problem: the square of Y2 is 4, what is y equal to?

Y = + 2 or - 2

Given a of X + B of y = 1 and B is not equal to y, find X

ay/(y-b)

Y = x ^ 2 + ax-3, both greater than or equal to - 1, find the range of a?
Quadratic function y = x ^ 2 + ax-3 (y = x.x + a.x-3)
The two roots x 1 and x 2 of a are greater than or equal to - 1

x1>=-1,x2>=-1
x1+1>=0,x2+1>=0
So addition and multiplication are greater than or equal to 0
Weida theorem
x1+x2=-a,x1x2=-3
(x1+1)+(x2+1)>=0
x1+x2+2>=0
-a+2>=0
a=0
x1x2+(x1+x2)+1>=0
-3-a+1>=0
A = 0, yes
So a

If x and y are nonzero real numbers such that | x | + y = 3 and | x | * y + x ^ 3 = 0, then x + y is equal to

│ x │ + y = 3 and │ x │ y + x ^ 3 = 0
x>0
x+y=3
xy+x^3=0
X ^ 2-x + 3 = 0, no real solution
x

As shown in the picture, a triangular piece of land should be evenly divided among farmers a, B and C. If ∠ C = 90 ° and ∠ B = 30 ° and the size and shape of the land obtained by these three farmers are the same, please try to divide it, draw it on the picture and prove it

Three congruent triangles are obtained by crossing BC with D and de ⊥ AB with e through D, where ∵ C = 90 °, B = 30 ° and ≁ cab = 60 ° and ≁ ad is the angular bisector of ≁ BAC, where ≁ bad = CAD = 12 ≁ cab = 30 ° and ≁ CD = 12ad, AC = adcos30 ° and ≁ AC = 3CD, and s △ ACD = 12 × AC × CD; ≁ DAE = 30 ° and ≁ DEA = 90 °, ad = 2DE and ≌ de = CD In this way, three lands of the same size and shape can be divided

Given that m (3,2), n (1, - 1), point P is on the Y axis, what is the coordinates of point P that makes PM pn the shortest

The coordinate of M 'is (- 3,2), and the equation of M' n is y = - 3 / 4x-1 / 4
The coordinates of its intersection with the y-axis are (0, - 1 / 4). This is the point P

Given: a 2 + 3A - 1 = 0, find the value of a 3 + 10 a 2 + 2003

a^2+3a=1
3a^3+10a^2+2003=3a(a^2+1)+a^2+2003=a^2+3a+2003=1+2003=2004

It's circle, coordinate, tangent equation
Now I'm learning hyperbola. I don't remember the circle of senior 1
C: X ^ 2 + y ^ = 17 has a point a (4, - 1) on the circle
The tangent equation passing through point a is 4x-y = 17
Why on earth?

From the meaning of the title
Center C (0,0)
K1 is the slope of a C
K1=（0+1）/（0-4）=-1/4
K2 is the slope of tangent equation
K2*K1=-1
K1=4
So Y-1 = 4 (x + 4)
4X-Y=17

If x 1, x 2 are two real roots of the equation x 2 - (2k + 1) x + K 2 + 1 = 0, and x 1, x 2 are greater than 1. (1) find the value range of real number k; (2) find the value of K if x 1, x 2 = 12

(1) The two roots of the equation X2 - (2k + 1) x + K2 + 1 = 0 are greater than 1, so that f (x) = X2 - (2k + 1) x + K2 + 1 ∧ Δ = 4k-3 ≥ 0, 2K + 12 > 1F (1) > 0, the solution is 34 ≤ K < 1 (2) ∧ x1x2 = 12, ∧ 2x1 = X2, ① X1 + x2 = 2K + 1, ② x1 ∧ x2 = K2 + 1 & nbsp; & nbsp; & nbsp; and ③

As shown in the figure, in the quadrilateral ABCD, ∠ DAB = 90 ° and ∠ DCB = 90 ° E and F are the midpoint of BD and AC respectively
_
A
_
B
_
C
_
D
_
E
_
F

Connecting AF, CF
∵∠ DAB = ∠ BCD = 90 ° f is the midpoint of BD
∴AF=1/2BD,CF=1/2BD
∴FA =FC
∵ e is the midpoint of AC
∴EF⊥AC