Factorise and solve x^2 -4x -12=0
x2 - 4x -12 is a quadratic equation with a general formula. It can be factorised by into brackets and solved.By looking at the equation, the last term is negative so one number in the factorised form must be negative. The coefficient in front of x is also negative, hence the larger number of the 2 is negative. Now we can start to look at combinations of numbers that fit this criteria that multiply together to make -12 and add together to make -4. There are only two combinations that fit this criteria, -2 & 6 and 2 & -6. As we stated above, the larger number must be negative, so the equation can be factorised to (x-6)(x+2). When this equation equals zero, there are 2 possible solutions of x values where this is true. For the equation to be zero, each bracket must equal zero. Therefore if x= 6 or -2, then the overall equation is 0 and has been solved.
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