Question

use the quadratic formula to solve the equation
-x^2+7x=5

Answer 1

A. \[-\frac{ 7 }{ 2 }\pm \frac{ \sqrt{29} }{ 2 }\]
B. \[\frac{ 7 }{ 2 }\pm \frac{ \sqrt{29} }{ 4}\]
C. \[\frac{ 7 }{ 2 }\pm \frac{ \sqrt{29} }{ 2 }\]
D. \[\frac{ 7 }{ 4 }\pm \frac{ \sqrt{29}}{ 2 }\]

Answer 2

Hi, Rockie,

How about subtracting 5 from both sides of the equation?

Can you then identify the values of the coefficients a, b and c of the resulting quadratic equation in standard form?

Answer 3

so it would be -x^2+7x-5
then what else do you do ?

Answer 4

Rockie, please identify the values of the three coefficients:
The coefficient of x^2 is -1, so a = -1
That of x is 7, so b = 7
The constant term is -5, so c = -5.

Remember the quadratic formula?

-b plus or minus Sqrt(b^2 - 4ac)
x=----------------------------
2a

Substitute the values of your a, b and c into this formula. Compare your results to the four possible answers which you've shared.

Answer 5

im so confused o.O

Answer 6

Rockie, I'm sure you've seen the quadratic formula before. It's almost always written in terms of 3 variables, a, b and c. You have values for a, b and c, so please substitute them into the quadratic formula to obtain the x values which are the solutions you've been seeking.

Answer 7

okay i did it and i got B is that right ?