Arthur D. answered 07/21/18
Tutor
4.9
(338)
Forty Year Educator: Classroom, Summer School, Substitute, Tutor
x=Sarah's age
x+6=Leah's age
(x)(x+6)=135
x^2+6x=135
x^2+6x-135=0
135=3*3*3*5=(3*3)*(3*5)=9*15 and 15-9=6, the coefficient of the middle term
factor
(x+15)(x-9)=0
x-9=0
x=9 years old for Sarah
x+6=15 years old for Leah