how to factor 5s ​2 +19s -4? (step by step)

how to factor 5s^2 +19s -4?

 

You need to find 2 numbers that multiply to 5*-4=-20   (so one is neg and one is pos)

 

and add to +19        (so the 'big' one is positive)

 

they would be +20 and -1

 

split   19s up into  20s-1s

 

\(5s^2+19s-4\\ =5s^2+20s-1s-4\\ \mbox{factorise in pairs}\\ =5s(s+4)-1(s+4)\\ =(5s-1)(s+4)\)

 

That is as far as you can go :))

5s² +  19s -4

(5s -1)(s +4)

s= { 1/5 , -4 }