Solve 20x-42x/4

$$20 x - \frac { 42 x } { 4 }$$

Evaluate

$$\frac{19x}{2}$$

Solution Steps

Divide 42x by 4 to get \frac{21}{2}x.

$$20x-\frac{21}{2}x$$

Combine 20x and -\frac{21}{2}x to get \frac{19}{2}x.

$$\frac{19}{2}x$$

Differentiate w.r.t. x

$$\frac{19}{2} = 9\frac{1}{2} = 9.5$$

Steps Using Definition of a Derivative

Divide 42x by 4 to get \frac{21}{2}x.

$$\frac{\mathrm{d}}{\mathrm{d}x}(20x-\frac{21}{2}x)$$

Combine 20x and -\frac{21}{2}x to get \frac{19}{2}x.

$$\frac{\mathrm{d}}{\mathrm{d}x}(\frac{19}{2}x)$$

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

$$\frac{19}{2}x^{1-1}$$

Subtract 1 from 1.

$$\frac{19}{2}x^{0}$$

For any term t except 0, t^{0}=1.

$$\frac{19}{2}\times 1$$

For any term t, t\times 1=t and 1t=t.

$$\frac{19}{2}$$