Beth tells her mom she got a great deal on a new dress. It only costs $54.57 including tax of 7%. Her mom asks about the original price. Beth says she only knows it was 40% off. What was the original price without tax?

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

(x) - (y) = (1 + 4i)