Question

using factor theorem,show than(x-5) is a factor of the polynomial 2x3-5x-28x+15​

Answer 1

Correct Question :

Using Factor Theorem , show that (x - 5) is a fcator of the polynomial 2x³ - 5x² -28x + 15 .

Given :

• A polynomial 2x³ - 5x² - 28x + 15 .

To Find :

• ( x - 5 ) is a factor of 2x³ - 5x² - 28x + 15 .

Solution :

$\longmapsto\tt{x-5=0}$

$\longmapsto\tt\bf{x=5}$

Putting x = 5 :

$\longmapsto\tt\bf{{2x}^{3}-{5x}^{2}-28x+15}$

$\longmapsto\tt{{2(5)}^{3}-{5(5)}^{2}-28(5)+15}$

$\longmapsto\tt{2(125)-5(25)-140+15}$

$\longmapsto\tt{250-125+140-15}$

$\longmapsto\tt{125-140+15}$

$\longmapsto\tt{-15+15}$

$\longmapsto\tt\bf{0}$

So , (x-5) is a factor of 2x³-5x²-28x+15 ....