How do you solve #x^2-2x-15=0#?
1 Answer
Nov 7, 2017
Explanation:
#"given the equation in standard form"#
#•color(white)(x)ax^2+bx+c=0#
#"factorise by considering the factors of the product a-c"#
#"which sum to + b"#
#"the factors of - 15 which sum to - 2 are - 5 and + 3"#
#rArr(x-5)(x+3)=0#
#"equate each factor to zero and solve for x"#
#x+3=0rArrx=-3#
#x-5=0rArrx=5#
#rArrx=-3" or "x=5" are the solutions"#
