The operation  is defined on the set R of real numbers by ab=ab+a. Determine whether or not the operation  is associative.​

Please I need help.

ab=ab+a

We need to check the following:

(ab)c=a(bc) or not

LHS

(ab)c=(ab+a)c

=(ab+a)c+(ab+a)

=abc+ac+ab+a

RHS

a(bc)=a(bc+b)

=a(bc+b)+a

=abc+ab+a

as LHS ≠ RHS, the operation is not associative

Step-by-step explanation:

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.

the answer is 62.8 cubic units