(10•10 to the power of 2) - ( 7.79• 10 to the power of 3)

10 * 10^2 - 7.79* 10^3

they have to be to the same power to add or subtract

change 10*10^2 to proper scientific notation  (only 1 number before the decimal) 1*10^3

1*10^3 - 7.79*10^3 = (1-7.79) * 10^3=-6.79*10^3

step-by-step explanation:

my gg bhitch

area of part 1:

a1=base*height/2=(8+2)*(8-2-2-1)/2=10*3/2=15 ft^2

area of part 2:

a2=length*width=(8+2)*1=10 ft2

area of part 3:

a3=length*width=8*2=16 ft2

total shaded area : a1+a2+a3=41 ft2

total area of the reactangle : a=16*8=128 ft2

total area of the nonshaded region : 128-41=87 ft2