Question Number 1 :
For this equation 2*x^2 - 3*x - 2 = 0 , answer the following questions :
A. Find the roots using Quadratic Formula !
Answer Number 1 :
The equation 2*x^2 - 3*x - 2 = 0 is already in a*x^2+b*x+c=0 form.
So we can imply that the value of a = 2, b = -3, c = -2.
1A. Find the roots using Quadratic Formula !
Use abc formula and you get either
x1 = (-b+sqrt(b^2-4*a*c))/(2*a) or x2 = (-b-sqrt(b^2-4*a*c))/(2*a)
As a = 2, b = -3 and c = -2,
we just need to subtitute the value of a,b and c in the abc formula.
Which produce x1 = (-(-3) + sqrt( (-3)^2 - 4 * (2)*(-2)))/(2*2) and x2 = (-(-3) - sqrt( (-3)^2 - 4 * (2)*(-2)))/(2*2)
Which is the same as x1 = ( 3 + sqrt( 9+16))/(4) and x2 = ( 3 - sqrt( 9+16))/(4)
Which is the same with x1 = ( 3 + sqrt( 25))/(4) and x2 = ( 3 - sqrt( 25))/(4)
So we get x1 = ( 3 + 5 )/(4) and x2 = ( 3 - 5 )/(4)
The answers are x1 = 2 and x2 = -0.5
參考: Just google up using this keyword :
quadratic solver orimath
Ok so the quadratic equation is ax^2+bx+c=0. In your problem a=2, b= -3, and c= -3. Assuming you know the quadratic formula, plug these numbers in and calculate x. You should have two possible answers for x because of the plus or minus in the quadratic formula. After I plugged the numbers in I got x=2 and x= -1/2 as the two answers. Remember order of operations when you plug those numbers in and you should be OK.