How do you solve #2q+q^2=15#?

1 Answer
Don't Memorise
Jun 17, 2015

#color(red)( q=3, q=-5#

Explanation:

#2q+q^2=15#
#q^2 + 2q-15=0#

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

Factorising by splitting the middle term

#q^2 + 5q - 3q -15=0#
#q(q + 5) - 3(q +5)=0#
#(q - 3)(q +5)=0#

Equating with zero :
# q-3 = 0, q=3#
# q+5 = 0 , q=-5#
Thus the solutions are:
#color(red)( q=3, q=-5#

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