The sum of the polynomials (3x^2 - 5x - 7) and (-9x^3 + 4x^2 - 9) has to be determined.
3x^2 - 5x - 7 + (-9x^3) + 4x^2 - 9
take the terms with the same power of x together
=> -9x^3 + 3x^2 + 4x^2 - 5x - 7 - 9
=> -9x^3 + 7x^2 - 5x - 16
The sum of (3x^2 - 5x - 7) and (-9x^3 + 4x^2 - 9) is -9x^3 + 7x^2 - 5x - 16
In the summation of polynomial, the coefficient of the term with the same variable should be added together.
For example, x^2 with the coefficient 3 should be added to 4x^2, resulting in (4+3)x^2 = 7x^2
In this way, the calculation can be done:
(3x^2-5x-7)+(-9x^3+4x^2-9) = -9x^3+(3+4)x^2-5x-(7+9)