principle of zero products

[caughn4]

(7x +5)(x = 4)(x-2)=0

could someone explain this to me

 

[Denis]

(7x + 5)(x + 4)(x - 2) = 0

That's the factoring of equation 7x^3 + 19x^2 - 46x - 40 = 0

If (7x + 5)(x + 4)(x - 2) = 0, then at least one of (7x + 5) or (x + 4) or (x - 2) equals 0; so:

7x + 5 = 0 ; x = -5/7
OR
x + 4 = 0 ; x = -4
OR
x - 2 = 0 ; x = 2

Did your teacher not teach you this?

 

[caughn4]

Thank you Denis...I am having a lot of trouble. I can't get into the tutoring lab and they don't know why. Thanks for your help. They gave me intermediat algebra and i have never taken algebra before except in high school and that was over 25 yrs ago. Thank you again!