Can u plz help out a mate or a friends here

Step-by-step explanation:

To solve means to find the x values of the equation:

-16x²+56x +72 =0; factor -8

-8*( 2x² -7x +9) =0

if we multiply two numbers and the answer is 0 then at least one of the numbers is 0. -8 is not 0 so 2x² -7x +9 must be 0. So you can further ignore the -8 in order to find the x.

2x² -7x +9 = 0 ; rewrite -7x as 2x-9x so you can factor

2x² +2x -9x +9 = 0

2x(x+1) -9(x+1) = 0 ; factor (x+1)

(x+1)(2x-9) = 0

Now again we have the product of two numbers is = 0

x+1 =0 ; x= -1

2x-9 =0 ; 2x=9 so x= 9/2

9 sandwiches per hour

step-by-step explanation:

when we have a rate, we want a 1 in the denominator

27/3 = 9

27 sandwiches/ 3 hours = 9 sandwiches/hour