What are the equations and how to solve it?

To solve an equation is to find the solution which are the value number functions that fulfill the conditional stated by the equation consisting generally of two expressions related by an equality sign when seeking a solution one or more free variables are designated as unknowns.

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