Question

Some of the steps in the derivation of the quadratic formula are shown.

Answer 1

Answer:

(C)The square root of terms separated by addition and subtraction cannot be calculated individually.

Step-by-step explanation:

In Step 7:

$\dfrac{\pm\sqrt{b^2-4ac} }{2a} =x+\dfrac{b }{2a}$

The expression $\pm\sqrt{b^2-4ac}$ cannot be written as $b \pm\sqrt{4ac}$. This is as a result of the fact that square roots of terms separated by addition and subtraction cannot be calculated individually.

Take these examples:

$\sqrt{9-4} =\sqrt{5} \\\sqrt{9}-\sqrt{4}=3-2=1\\ Clearly \sqrt{5}\neq 1\\ Similarly\\\sqrt{9+4} =\sqrt{13} \\\sqrt{9}+\sqrt{4}=3+2=5\\ Clearly \sqrt{13}\neq 5$

Answer 2

Answer:

C

Step-by-step explanation:

Took the test on edge.