How do you solve # h^2 + 10h = -21#?

1 Answer
Jun 24, 2015

Answer:

The solutions are
# color(green)( h = -3 , h = -7#

Explanation:

# h^2 + 10h + 21 = 0#

Here, we can first factorise the expression and then find the solutions:

Factorising by splitting middle term:

# h^2 + 10h + 21 = 0#
# h^2 +color(green)(3h + 7h) + 21 = 0#
# h( h+3) +7( h+3) = 0#
#(h+3)(h+7) = 0#
Equating the factors with zero to obtain solutions:
# h+3 = 0 ,color(green)( h=-3#
# h+7 = 0 , color(green)(h=-7#