# What is the equation of the line normal to #f(x)=2x^2-x - 1# at #x=5#?

##### 1 Answer

or

#y = -1/19 x + 841/19

#### Explanation:

Remember

Slope of normal line is

**Step 1:** Find derivative, to determine the slope of tangent line

#f'(x) = 4x -1#

**Step 2:** Find the slope of the tangent line

#m= f'(5) = 4(5) -1 = 19#

**Slope of normal line is**

**Step 3** Determine the

#f(5) = 50-5-1#

#f(5) = 44#

Ordered pair

Step 4: Write the equation of the line using point slope formula

#y-44 = -1/19 x +5/19 #

#y = -1/19x + 5/19 +44#

#y = -1/19x +44 5/19 #

or