2a. let a=1 and b-l find all values of a, b, c and d for which the matrices a and b commute? b. find all values of c for which the following matrix is invertible l1 1

we need to find the determinant.  

= -1(7*9 - 3* -3)(4*9 - 3*3) -2(4*9 -7*3)

= -1(63-27) +3 (36 - 9) -2( 36- 21)

= -1(36)+3(27)-2(15)

= -36+81-30

= 15

the camry sales+accord sale=828,000. to make it so the two numbers are 18 thousand apart and still equal 828,000, you first need to find out what half of 828,000 is. 828,000/2=414,000. for the two numbers to equal 828,000, you have to add the same amount as you subtract from the middle. in this case, the number is 9,000 because it's half of 18,000. to equal 828,000, you have to add 9,000 to 414,000 for the camry and subtract 9,000 from 414,000 for the accord. 414,000+9,000=423,000.

414,000-9,000=405,000.

423,000+405,000=828,000.

423,000-405,000=18,

hope it