Solve 9+2x^3-7x^3-2x^3

$$9 + 2 x ^ { 3 } - 7 x ^ { 3 } - 2 x ^ { 3 }$$

Evaluate

$$9-7x^{3}$$

Solution Steps

Combine 2x^{3} and -7x^{3} to get -5x^{3}.

$$9-5x^{3}-2x^{3}$$

Combine -5x^{3} and -2x^{3} to get -7x^{3}.

$$9-7x^{3}$$

Differentiate w.r.t. x

$$-21x^{2}$$

Steps Using Derivative Rule for Sum

Combine 2x^{3} and -7x^{3} to get -5x^{3}.

$$\frac{\mathrm{d}}{\mathrm{d}x}(9-5x^{3}-2x^{3})$$

Combine -5x^{3} and -2x^{3} to get -7x^{3}.

$$\frac{\mathrm{d}}{\mathrm{d}x}(9-7x^{3})$$

The derivative of a polynomial is the sum of the derivatives of its terms. The derivative of a constant term is 0. The derivative of ax^{n} is nax^{n-1}.

$$3\left(-7\right)x^{3-1}$$

Multiply 3 times -7.

$$-21x^{3-1}$$

Subtract 1 from 3.

$$-21x^{2}$$