Y = X2 - 4X - 5
set to zero
X2 - 4X - 5 = 0
X2 - 4X = 5
halve the linear term ( - 4 ) then square it and add that result to both sides
X2 - 4X + 4 = 5 + 4
factor on the left and gather terms together on the right
(X - 2)2 = 9
(X - 2)2 - 9 = 0
==============vertex form
(2, - 9)
======vertex
The vertex of a parabola is the minimum or maximum value of the parabola. To find the maximum/minimum of a parabola complete the square: x² + 4x + 5 = x² + 4x + 4 - 4 + 5 = (x² + 4x + 4) + (-4 + 5) = (x + 2)² + 1 As (x + 2)² is greater than or equal to 0, the minimum value (vertex) occurs when this is zero, ie (x + 2)² = 0 → x + 2 = 0 → x = -2 As (x + 2)² = 0, the minimum value is 0 + 1 = 1. Thus the vertex of the parabola is at (-2, 1).
In ordinary mathematics, assuming that x = X and that X2 denotes x2 or x-squared, there cannot be a counterexample since the statement is TRUE. However, there are two assumptions made that could be false and so could give rise to counterexamples. 1. x is not the same as X. If, for example X = 4x then X = -20 so that X2 = 400. 2a. X2 is not X2 but X times 2. In that case X2 = -10. 2b. X2 is x2 modulo 7, for example. Then X2 = 4.
-5
3x+5= 4x-10+10 +103x+15= 4x-3x -3x15=X
2x + 5 = 7 - 4x ie 2x + 4x = 7 - 5 ie 6x = 2 x = one third.
Example function.Y = X2 - 4X + 5set to 0X2 - 4X + 5 = 0X2 - 4X = - 5Now, halve the linear coefficient, square it and add it to both sidesX2 - 4X + 4 = - 5 + 4gather terms on the right and factor on the left(X - 2)2 = -1==============Vertex form.(2, - 1)=======Vertex.
2x2= 4
Their sum is 4.
The vertex is at (5, -5).
Since the polynomial has three zeroes it has a degree of 3. So we have:(x - -5)[x - (2 + i)][x - (2 - i)]= (x + 5)[(x - 2) - i][(x - 2) + i]= (x + 5)[(x - 2)2 - i2]= (x + 5)[x2 - 2(x)(2) + 22 - (-1)]= (x + 5)(x2 - 4x + 4 + 1)= (x + 5)(x2 - 4x + 5)= x(x2 - 4x + 5) + 5(x2 - 4x + 5)= x3 - 4x2 + 5x + 5x2 - 20x + 25= x3 + x2 - 15x + 25Thus,P(x) = x3 + x2 - 15x + 25
You can work this out by taking the derivative of the equation with respect to y, and finding where that derivative (ie. the slope of the curve's tangent) equals 0: y = -x2 + 4x - 9 ∴ dy/dx = -2x + 4 Let dy/dx = 0: 0 = -2x + 4 ∴ x = 2 Now find the corresponding y co-ordinate by plugging that value for x into the original equation: y = -(2)2 + 4(2) - 9 ∴ y = - 4 + 8 - 9 ∴ y = -5 So the vertex of that parabola is located at the point (2, -5).
Add 4 to both sides. To complete the square, take half the x coefficient into the bracket: (x + 4/2)2 = (x + 2)2 = x2 + 4x + 4 Comparing with the original, need to add 4 to both sides of x2 + 4x = 5: (x2 + 4x) + 4 = (5) + 4 ⇒ x2 + 4x + 4 = 9 ⇒ (x + 2)2 = 9
X2 - 4X - 5 as an expression, or equation is factorable when the question, what two factors of - 5 add to - 4 is answered ( X + 1)(X - 5) X = - 1 ------------and X = 5 ---------------
The coordinates will be at the point of the turn the parabola which is its vertex.
Assuming the missing operator before the final 5 is subtract, then: x2 - 4x - 5 = (x + 1) (x - 5) ⇒ x = -1 or 5. If it is add, there are no real root solution. The solution to the latter case is: x2 - 4x + 5 = (x - 2 - i)(x - 2 + i) ⇒ x = 2 + i or x = 2 - i.
f(x) = x2-4x-5 = x2-5x+x-5 = x(x-5)+1(x-5) = (x+1)(x-5) Factors of f(x) are (x+1) and (x-5).
If that's -5 the answer is (x - 5)(x + 1)