If A is the 2 × 2 matrix given by A = a b c d and if ad − bc ≠ 0, the inverse is given by A−1 = 1 ad − bc d −b −c a . Use the formula above to find the inverse of the 2 × 2 matrix (if it exists). (If an answer does not exist, enter DNE in any single blank.)

See the attached file !

Step-by-step explanation:

the least common denominatore of 7 and 2 is 9

step-by-step explanation:

7+2=9

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

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40