Lösung 2.1:1e
Aus Online Mathematik Brückenkurs 1
If we use the rule for squaring \displaystyle (a-b)^2 = a^2-2ab+b^2 with \displaystyle a=x and \displaystyle b=7, we obtain directly that
An alternative is to write the square as \displaystyle (x-7)\cdot (x-7) and then multiply the brackets in two steps
In the line that has been marked with an asterisk, we have removed the bracket and at the same time changed signs on all terms inside the bracket.
