Chapter 4.6, Problem 43HP

To determine

The correct value of discriminant.

Answer to Problem 43HP

Jonathan is correct.

Explanation of Solution

Given:

  $3x^2-5x=7$

Calculation:

Using formula to determine discriminant,

  $b^2-4ac$

Now,

The quadratic equation,

  $\begin{array}{l}3x^2-5x=7\\ 3x^2-5x-7=0\end{array}$

Here,

  $\begin{array}{l}a=3,\\ b=-5,\\ c=-7\end{array}$

Therefore,

Discriminant,

  $\begin{array}{l}\text{D}={\left(-5\right)}^2-4\left(3\right)\left(-7\right)\\ \text{D}=25-\left(-84\right)\\ \text{D}=25+84\\ \text{D}=109\end{array}$

So,

Jonathan is correct.

Reasoning,

Tama has taken wrong value of c.

Therefore, the value of discriminant is incorrect whereas Jonathan has chosen the correct value of c. So, his discriminant value is correct.