solve the equation 2x^2 - 18x +4=0 by quadratic formula
Answers
Answer:
The form ax2 + bx + c = 0 is called standard form of a quadratic equation. Before solving a quadratic equation using the Quadratic Formula, it's vital that you be sure the equation is in this form. If you don't, you might use the wrong values for a, b, or c, and then the formula will give incorrect solutions.
Step-by-step explanation:
2x2-18x-4=0
Two solutions were found :
x =(9-√89)/2=-0.217
x =(9+√89)/2= 9.217
Step by step solution :
Step 1 :
Equation at the end of step 1 :
(2x2 - 18x) - 4 = 0
Step 2 :
Step 3 :
Pulling out like terms :
3.1 Pull out like factors :
2x2 - 18x - 4 = 2 • (x2 - 9x - 2)
Trying to factor by splitting the middle term
3.2 Factoring x2 - 9x - 2
The first term is, x2 its coefficient is 1 .
The middle term is, -9x its coefficient is -9 .
The last term, "the constant", is -2
Step-1 : Multiply the coefficient of the first term by the constant 1 • -2 = -2
Step-2 : Find two factors of -2 whose sum equals the coefficient of the middle term, which is -9 .
-2 + 1 = -1
-1 + 2 = 1
Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored
Equation at the end of step 3 :
2 • (x2 - 9x - 2) = 0
Answer:
D = b square - 4ac
= 18 square - 4*2*4
= 324- 32
= 292
x = - b + root D / 4a
= -18 + root 292 / 8
= -18 + 2 root 73 / 8
now solve it
then use this formula to find other zero
- b - root D /4a
root D take in negative