Fortifications are militaryconstructions designed for defensivewarfare. They have been used for many thousands of years, in a variety of increasingly complex designs. The practice of improving an area's defense is also known as "fortification". Many military installations are known as forts, although they are not always "fortified".
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<math>x^2+\frac{b}{a}x=-\frac{c}{a}.</math>
The equation is now in a form in which we can conveniently complete the square[?]. To "complete the ...