Question

$h { } ^{2} + 6h = 72$

Answer 1

h^2 + 6h -72 = 0

h^2 +(12-6)h -72 =0

h^2 +12 -6h -72 = 0

h(h+12) -6(h+12) = 0

(h+12)(h-6) = 0

then 

h+12 = 0   and h-6 = 0

and  h=-12  OR  h= 6

mostly we takes the positive value 

then h=6

i hope this will help you


-by ABHAY