Solve -3x*7*-x=

$$-3x \times 7 \times -x=$$

Evaluate

$$21x^{2}$$

Solution Steps

Multiply -3 and 7 to get -21.

$$-21x\left(-x\right)$$

Multiply -21 and -1 to get 21.

$$21xx$$

Multiply x and x to get x^{2}.

$$21x^{2}$$

Differentiate w.r.t. x

$$42x$$

Steps Using Definition of a Derivative

Multiply -3 and 7 to get -21.

$$\frac{\mathrm{d}}{\mathrm{d}x}(-21x\left(-x\right))$$

Multiply -21 and -1 to get 21.

$$\frac{\mathrm{d}}{\mathrm{d}x}(21xx)$$

Multiply x and x to get x^{2}.

$$\frac{\mathrm{d}}{\mathrm{d}x}(21x^{2})$$

The derivative of ax^{n} is nax^{n-1}.

$$2\times 21x^{2-1}$$

Multiply 2 times 21.

$$42x^{2-1}$$

Subtract 1 from 2.

$$42x^{1}$$

For any term t, t^{1}=t.

$$42x$$