325,377 views
37 votes
37 votes
Please help me with my son math problem he keeps getting it wrong and we have a chance to redo it. I have included the image of the problem please help

Please help me with my son math problem he keeps getting it wrong and we have a chance-example-1
User Aboobakkar P S
by
3.0k points

1 Answer

23 votes
23 votes

Recall that the discriminant of a quadratic equation:


ax^2+bx+c=0

is:


\Delta=b^2-4ac\text{.}

We know that:

1) If Δ=0 then the quadratic equation has one double root.

2) If Δ>0 then the quadratic equation has two different real roots.

3) If Δ<0 then the quadratic equation has two different nonreal roots.

Now, we can rewrite the given equation as follows:


5y^2-18y+4=0.

The discriminant of the above equation is:


\Delta=(-18)^2-4(5)(4)\text{.}

Simplifying the above result we get:


\begin{gathered} \Delta=324-80 \\ =244. \end{gathered}

Since:


\Delta>0.

Then the given equation has two different real solutions.

Finally, notice that:


\sqrt[]{244}=2\sqrt[]{61}

Therefore the solutions are both irrational.

Answer: Last option.

User Pulsar
by
2.7k points