Answer:
( x + 3 ) ( x - 5 )
Step-by-step explanation:
When factorising quadratic equations you have to remember 3 things. Factors , sum and product. The standard way quadratic equation are formed is ax² + bx + c
→ The sum is the 'b' value, two number which add to this
The product is the 'c' value, two number which multiply to this
x² - 2x - 15
We need to two numbers which add to -2 and multiply to -15. Those two numbers are -5 and 3 so
x² - 5x + 3x - 15
→ Take out the factors separately
x ( x - 5 ) + 3 ( x - 5 )
( x + 3 ) ( x - 5 )
