Question

Which are the roots of the quadratic function f(b) = 62 – 75? Select two options.

Answer 1

Answer:

$b = 5 \sqrt{3} \ or\ b = -5 \sqrt{3}$

Step-by-step explanation:

Given

$f(b) = b^2 - 75$

Required

Determine the roots

To get the root of the function, then f(b) must be 0;

i.e. f(b) = 0

So, the expression becomes

$0 = b^2 - 75$

Add 75 to both sides

$75 + 0 = b^2 - 75 + 75$

$75 = b^2$

Take square roots of both sides

$\sqrt{75} = \sqrt{b^2}$

$\sqrt{75} = b$

Reorder

$b = \sqrt{75}$

Expand 75 as a product of 25 and 3

$b = \sqrt{25*3}$

Split the expression

$b = \sqrt{25} *\sqrt{3}$

$b = \±5 *\sqrt{3}$

$b = \±5 \sqrt{3}$

$b = 5 \sqrt{3} \ or\ b = -5 \sqrt{3}$

The options are not clear enough; however the roots of the equation are $b = 5 \sqrt{3} \ or\ b = -5 \sqrt{3}$