Find the value of X in the equation X^2 + 9X - 22 = 0
There are 3 ways of solving this but I will go through the 2 that are necessary for GCSE level
Firstly - 22 can only be made by 122 or 211 -------> 11 - 2 = 9 therefore 11 and -2 are needed to make the roots of the equation------> (x + 11)(x-2)=0 --------> for the equation to equal 0 either x+11 or x-2 has to equal 0 -------> therefore x= -11 or x=2
Second way: quadratic formula - this one is best for when the numbers are not as nice as the example and the roots would involve a lot of decimal places
Use the formula (-b +/- _/b^2-4ac)/2a where the equation takes the form aX^2 + bX + c = 0 -------> values should be substituted in and the same answers should be found - This can be explained a lot better in the interview
Overall the answer is X = -11 or +2
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