Question

(x-3)³+5=x³+7x²-1
plz snswer​

Answer 1

Step-by-step explanation:

x^3 -9 -9x(x-3)+5=x^3 + 7x^2 -1

-9 -9x^2 + 27x = 7x^2 -1

16x^2+8-27x=0

Answer 2

Correct Question:

Prove the below equation as quadratic:

(x - 3)³+ 5 = x³ + 7x² - 1

Solution:

Given equation:

(x - 3)³ + 5=x³ + 7x²- 1

Identity to be used to split it:

(x - y)³ = x³ - y³ - 3x²y + 3xy²

Spilt the term using this identity:

(x - 3)³ = x³ - 27 - 3(x²)(3) + 3(x)(9)

= x³ - 27 - 9x² + 27x

Put this value in the equation:

(x - 3)³ + 5 = x³ + 7x² - 1

=> x³ - 27 - 9x² + 27x + 5 = x³ + 7x² - 1

Take every term to LHS [Note that the signs change while transposing]:

=> x³ - 27 - 9x² + 27x + 5 - x³ - 7x² + 1 = 0

=> -16x² + 27x - 21 = 0

=> -(16x² - 27x + 21) = 0

=> 16x² - 27x + 21 = 0

Note that a quadratic equation is an equation with degree 2.

Since this simplified equation has a degree 2, it is a quadratic equation.