That all dolphins have different sizes and are mostly different ages
D because using the y=mx+b the slope(mx) is 1/2 (rise over run) and it starts at point 0,-2(b) since y is always 0 and -2 is the x value
8-8^-1
=8-1/8 <<< 8*8=64 then 64-1=63
=63/8
in decimal(7.875)
You would do
51-5= 46
then you would divide
46/2= 23
so Susan is
23+5=28
Susan is 28 years old and her sister is 23
28+23=51
