6/a - 4/b = 1 and 9/a - 8/b = 1

a = 3 ; b = 4

Step-by-step explanation:

Eqn.1 =

Eqn.2 =

Both the eqns have RHS (Right Hand Side) equal. So,

Cancelling ab from both the denominators of both the sides,

Putting the value of a in Eqn.1,

Putting the value of b in the value of a

walter needs to make at least 5 more cookies but no more than 40. 5 ≥ x ≥ 40;

step-by-step explanation:

walter has to make a minimum of 20 cookies. he already has 15 cookies made, so he must make 5 more to meet the minimum.

the maximum amount of cookies he can make is 55. he already has 15, so he has to make no more than 40 more cookies to meet the maximum.

9 x 8 divided by (5-3)=36