Find the midpoint of ab with a(-3,12) and b(21,-8)

x=x2-x1/2 ; y=y2-y1
 utilizando esa formula y sustituyendo nos quedaria de la siguente manera x=2+3/2 ; y=-8-12/2
resolviendo las respuestas son x=5/2 ; y=-10

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post