Question

A quadratic equation is shown below:

9x2 - 16x + 60 = 0

Part A: Describe the solution(s) to the equation by just determining the radicand. Show your work.

Part B: Solve 4x2 + 8x - 5 = 0 by using an appropriate method. Show the steps of your work, and explain why you chose the method used.

Part C: Solve 2x2 -12x + 5 = 0 by using a method different from the one you used in Part B. Show the steps of your work.

Answer 1

@Hero

Answer 2

for part a would I solve by using the quadratic formula? @Hero

Answer 3

then for part b by finding the zeros?

Answer 4

and for part c by completing the square?

Answer 5

Yes, use the quadratic formula for part A

Answer 6

ok hang on one sec

Answer 7

Try factoring for part B

Answer 8

Complete the Square for part C

Answer 9

this is what I got for part A what does it mean??

Answer 10

ok factor for part b: (2x+5)(2x−1) which shows the x-intercepts of x=−5/2,1/2

Answer 11

Actually, what I believe you're supposed to do is use b^2 - 4ac to determine if part A has any real solutions.

Answer 12

Part C: x=3± 26‾‾‾√ 2

Answer 13

If b^2 - 4ac is negative, then the solutions for the equation for part A are not real.

Answer 14

ok thats what I did but i got that answer, so woulf that mean that it has no solutions??

Answer 15

so are they negative?

Answer 16

Compute b^2 - 4ac

Answer 17

there is not solutions because when you plug in 16^2 -4(9)(60) you get 32 - 2160 = -2128

Answer 18

@Hero

Answer 19

Well, whatever the number is, it IS negative, but the number is not correct.

Answer 20

would i only show my work up to there and then determine that there is no solutions @Hero

Answer 21

I believe that's the intent, yes.

Answer 22

ok thank you and for part b and c factor one and complete the square for the other?

Answer 23

Yes, correct.

Answer 24

but what would i put to say why i choose it?

Answer 25

also I have another question for you can you help? @Hero

Answer 26

Post it as a separate question.

Answer 27

@TheSmartOne what would I write to say why I choose factoring for part b and completing the square for part c?

Answer 28

Because there are only 3 ways to solve a quadratic equation - Factoring, Completing the Square, and the Quadratic Formula

so you had to chose one of them, and then chose another method. :)

Answer 29

thanks so much! @TheSmartOne