Use the following matrices, a, b, c and d to perform each operation. a = |3 1| |5 7| b = |4 1| |6 0| c = |-2 3 1| |-1 0 4| d = |-2 3 4| |0 -2 1| |3 4 -1| 40. a + b 41. b - a 42. 3c 43. cd 44. 2d + 3c

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.