1.)
2x^2 + x - 2 = 0
x = (-b ± sqrt(b^2 - 4ac))/(2a)
x = (-1 ± sqrt(1^2 - 4(2)(-2)))/(2(2))
x = (-1 ± sqrt(1 + 16))/4
x = (-1 ± sqrt(17))/4
x = (1/4)(-1 ± sqrt(17))
---------------------------------------
2.)
2x^2 + 5x = 1
2x^2 + 5x - 1 = 0
x = (-b ± sqrt(b^2 - 4ac))/(2a)
x = (-5 ± sqrt(5^2 - 4(2)(-1)))/(2(2))
x = (-5 ± sqrt(25 + 8))/4
x = (-5 ± sqrt(33))/4
ANS :
(1/4)(-5 ± sqrt(33))
2006-10-29 14:56:08
·
answer #1
·
answered by Sherman81 6
·
0⤊
0⤋
The general form of a quadratic equation in x is:
ax^2 +bx +c = 0 where a,b,c are constants and the solutions for x are given by the quadratic formula:
x = (-b +(or -) sqrt(b^2 -4ac))/2a
1. a=2, b=1, c= -2 so
x = (-1+(or -) sqrt(1-4*1*-2))/2
= (-1+(or-) sqrt(9))/2
= (-1+3)/2 = 1 or (-1-3)/2 = -2
Just be careful with the signs of the constants and of the product 4ac.
I'll leave 2 with you.
2006-10-29 22:36:39
·
answer #2
·
answered by Jimbo 5
·
0⤊
0⤋
Do you mean 'quadratic formula'?
It give the two solutions of a 2nd order equation
a is the coefficient of the squared term
b is the coef of the linear term
c is the constant
Note that the equation must be written to equal zero. Thus for eqn 2 you must move the 1 to the left side.
You just plug the a,b, and c into the quadratic equation and simplify.
2006-10-29 22:25:00
·
answer #3
·
answered by modulo_function 7
·
0⤊
0⤋
If ax^2+bx+c=0
x={-b+-sqrt[b^2-4ac]}/2a
we will use these formula to solve
qn1
x={-2+-sqrt[1+16]}/4
=-1/2+-1/4sqrt17
qn2
x={-5+-sqrt[25-8]}/4
=1/4[-5-sqrt17]
2006-10-30 09:16:12
·
answer #4
·
answered by openpsychy 6
·
0⤊
0⤋
You mean quadratic equations, right?
Use the quadratic formula to simplify.
If you don't know how to use the quadratic formula, go to:
purplemath.com and search for the quadratic formula lesson.
Purplemath.com will show you how easy it is to use the formula to solve your questions.
Guido
2006-10-29 22:32:54
·
answer #5
·
answered by Anonymous
·
0⤊
0⤋
the standard form of the equation is:
ax^2+bx+c
quadratic formula is:
x=(-b+_sq.root of(b^2-4ac))/2a
plug everything in and you will find the answers
(+_)=plus minus
2006-10-29 22:30:24
·
answer #6
·
answered by aznfobboytly 3
·
0⤊
0⤋