Question

Which equation has the solutions?

a) 3x2 – 5x + 7 = 0
b) 3x2 – 5x – 1 = 0
c) 3x2 – 10x + 6 = 0
d) 3x2 – 10x – 1 = 0

Answer 1

Option d is correct.

Explanation:

We have bee given the solution which is:

`x=(5\pm2√(7))/(3)`

Using:
`D=b^2-4ac`

And then
`x=(-b\pm√(D))/(2a)`

From the given equation we will check for D first and then we proceed because
`√(D)` is the initial step of the solution.

`3x^2-10x-1=0`

Here, a=3,b= -10 and c=-1.

Substituting the values in the formula to get the solution.

`D=(-10)^2-4(3)(-1)=112`

`x=(10\pm√(112))/(6)`

`x=(10\pm 4√(7))/(6)`

`\Rightarrow x=(5\pm2√(7))/(3)`

Option d is correct.