Question

What are the zeros of the function?

Answer 1

The function is:

f ( x ) = x² - x - 72

This is a quatdratic function. So we can find the zeroes of the function with the formula:

x 1/2 = ( - b +/- √(b² - 4 ac) ) / ( 2a )

And we have: a = 1, b = - 1 and c = - 72

x 1/2 = ( 1 +/- √((-1)² - 4 · 1· ( - 72 )) ) / 2

x 1/2 = ( 1 +/- √( 1 + 288 ) ) / 2

x 1/2 = ( 1 +/- √289 ) / 2

x 1/2 = ( 1 +/- 17 ) / 2

x 1 = ( 1 - 17 ) 2 = - 16 / 2 = - 8

x 2 = ( 1 + 17 ) / 2 = 18 / 2 = 9

Answer: The zeroes are - 8 and 9.