How do you solve #x^2+5x-84=0#?

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Answer 1 · 2015-08-02T06:20:28

The solutions for the expression are:
# color(blue)(x=7, color(blue)(x=-12#

#x^2+5x–84#

We can first factorise the above expression and then proceed towards finding the solution.

Factorising by splitting the middle term

#x^2+color(blue)(5x)–84 = x^2+color(blue)(12x -7x)–84#

#=x(x+12) - 7(x +12)#

#color(blue)((x-7)(x+12) # is the factorised form for the expression.

Now we can equate each factor with zero and obtain the solutions.

#x-7=0, color(blue)(x=7#
#x+12=0, color(blue)(x=-12#