Question 86338
2x^-1y^3 if x=2 and y=-1

2(2)^-1*(-1)^3

2*1/2*-1     (2*1/2 gets cancelled and we get 1)

1*-1

=-1

2) Express 7,200,000,000 in scientific notation

72*10^8

7.2*10^9

3) (1.4 times 10^7)(2.5 times 10^2)in scientific  notation

   
     3.5*10^10

4) -5x^4z,if x=-2 and z=3.

   plugin the value of x an d z

   -5(-2)^4(3)

   -5(32)(3)

   -5(96)
  
   -480