How do you solve #3x ^ { 2} - 6x - 72= 0#?

1 Answer
Apr 17, 2018

#x=-4" or "x=6#

Explanation:

#"take out a "color(blue)"common factor "3#

#rArr3(x^2-2x-24)=0#

#"to factor the quadratic"#

#"the factors of - 24 which sum to - 2 are - 6 and + 4"#

#rArr3(x-6)(x+4)=0#

#"equate each of the factors to zero and solve for x"#

#x-6=0rArrx=6#

#x+4=0rArrx=-4#