0
Since I can't show you graphs on Answers I must ask you to visualise a parabola that does cross the x-axis at two points. (It doesn't matter whether the parabola is 'open' at the top or at the bottom.) For example, we could consider the parabola
5x2 + 9x - 2
We find that it crosses the x-axis at x = 1/5 and x = -2. We call these solutions or roots of
5x2 + 9x - 2 = 0, and we can show that each of these solutions can be used to create a factor of the original parabola.
x = 1/5 yields the factor x - 1/5 :
which we demonstrate by dividing 5x2 + 9x - 2 by x - 1/5 to get 5x + 10 even (and we can check that x - 1/5 multiplied by 5x + 10 yields the original parabola).
x = -2 yields the factor x + 2 :
which we again demonstrate by dividing 5x2 + 9x - 2 by x + 2 to get 5x - 1 even.
The point of this is that when a parabola crosses the x-axis it has solutions that yield factors. However, if it doesn't cross the x-axis it cannot have solutions (because it cannot 'equal' zero), and therefore cannot be factored.
Add your answer:
Earn +20 pts
What do you get when you cross a mathmatician with a rubber band?
an equation
How is a proportion changed into a mathematical equation?
a proportion is an equation. a / b = c / d cross multiply: ad = bc then solve
Multiplying each numerator in the original rational equation by the denominator from the opposite side of the rational equation is known as?
cross-multiplying
Can you make a triangle out of a cross section for a cylinder?
No, you cannot.
How do you calculate the cross sectional area of a cube?
You cannot unless you know the angle of the plane which defines the cross section.
Can you write the equation of a parabola that doesn't cross the x-axis in factored form?
No.
Can a cross protect me from a ghost?
i guess cross doesnt have an effect on ghost...
Would the cross section of a satellite dish be modeled by a linear or a quadratic equation?
The satellite dish is a parabolic reflector. A parabola cannot be modeled by a linear equation because a linear equation is one that graphs as a straight line. It takes a second degree expression to plot it, and that means a quadratic equation.
When do you cross multiply to solve an equation?
When doing fractions, you may cross multiply.
What do you get when you cross a mathmatician with a rubber band?
an equation
Why doesnt the graph of a rational function cross its vertical asymptote?
It can.
How many cars cross the peace bridge each day?
it doesnt matter
How is a proportion changed into a mathematical equation?
a proportion is an equation. a / b = c / d cross multiply: ad = bc then solve
Multiplying each numerator in the original rational equation by the denominator from the opposite side of the rational equation is known as?
cross-multiplying
Can a cube have an octagonal cross section?
No, a cube cannot have an octagonal cross-section.
Why doesnt Santa Claus have a cross on his hat?
because he isnt a leader of god i guess?
What happens when you cross a cow and a sheep?
Nothing - cattle and sheep cannot be cross-bred.
