Solve by factoring 3x^2 - 19x - 40 = 0

(3x^2 - 19x) - 40=0 Multiply 3*-40=-120

Then find the factor which is - 19

Now using 2 factors ~ 3x2 - 24x + 5x - 40

We going to split it up

3x * (x-8)

Add your last two terms

5 * (x-8)

Then add up the 4 terms

(3x+5) * (x-8)

Which means x=8