Examples
f(x)=x2+12f(x)=x2+12 , (-3,4)(−3,4)
Step 1
Write f(x)=x2+12f(x)=x2+12 as an equation.
y=x2+12y=x2+12
Step 2
Step 2.1
The average rate of change of a function can be found by calculating the change in yy values of the two points divided by the change in xx values of the two points.
f(4)-f(-3)(4)-(-3)f(4)−f(−3)(4)−(−3)
Step 2.2
Substitute the equation y=x2+12y=x2+12 for f(4)f(4) and f(-3)f(−3), replacing xx in the function with the corresponding xx value.
((4)2+12)-((-3)2+12)(4)-(-3)((4)2+12)−((−3)2+12)(4)−(−3)
((4)2+12)-((-3)2+12)(4)-(-3)((4)2+12)−((−3)2+12)(4)−(−3)
Step 3
Step 3.1
Multiply the numerator and denominator of the fraction by 22.
Step 3.1.1
Multiply 42+12-((-3)2+12)4-(-3)42+12−((−3)2+12)4−(−3) by 2222.
22⋅42+12-((-3)2+12)4-(-3)22⋅42+12−((−3)2+12)4−(−3)
Step 3.1.2
Combine.
2(42+12-((-3)2+12))2(4-(-3))2(42+12−((−3)2+12))2(4−(−3))
2(42+12-((-3)2+12))2(4-(-3))2(42+12−((−3)2+12))2(4−(−3))
Step 3.2
Apply the distributive property.
2⋅42+2(12)+2(-((-3)2+12))2⋅4+2(-(-3))2⋅42+2(12)+2(−((−3)2+12))2⋅4+2(−(−3))
Step 3.3
Cancel the common factor of 22.
Step 3.3.1
Cancel the common factor.
2⋅42+2(12)+2(-((-3)2+12))2⋅4+2(-(-3))2⋅42+2(12)+2(−((−3)2+12))2⋅4+2(−(−3))
Step 3.3.2
Rewrite the expression.
2⋅42+1+2(-((-3)2+12))2⋅4+2(-(-3))2⋅42+1+2(−((−3)2+12))2⋅4+2(−(−3))
2⋅42+1+2(-((-3)2+12))2⋅4+2(-(-3))2⋅42+1+2(−((−3)2+12))2⋅4+2(−(−3))
Step 3.4
Simplify the numerator.
Step 3.4.1
Raise 44 to the power of 22.
2⋅16+1+2(-((-3)2+12))2⋅4+2(-(-3))2⋅16+1+2(−((−3)2+12))2⋅4+2(−(−3))
Step 3.4.2
Multiply 22 by 1616.
32+1+2(-((-3)2+12))2⋅4+2(-(-3))32+1+2(−((−3)2+12))2⋅4+2(−(−3))
Step 3.4.3
Raise -3−3 to the power of 22.
32+1+2(-(9+12))2⋅4+2(-(-3))32+1+2(−(9+12))2⋅4+2(−(−3))
Step 3.4.4
To write 99 as a fraction with a common denominator, multiply by 2222.
32+1+2(-(9⋅22+12))2⋅4+2(-(-3))32+1+2(−(9⋅22+12))2⋅4+2(−(−3))
Step 3.4.5
Combine 99 and 2222.
32+1+2(-(9⋅22+12))2⋅4+2(-(-3))32+1+2(−(9⋅22+12))2⋅4+2(−(−3))
Step 3.4.6
Combine the numerators over the common denominator.
32+1+2(-9⋅2+12)2⋅4+2(-(-3))32+1+2(−9⋅2+12)2⋅4+2(−(−3))
Step 3.4.7
Simplify the numerator.
Step 3.4.7.1
Multiply 99 by 22.
32+1+2(-18+12)2⋅4+2(-(-3))32+1+2(−18+12)2⋅4+2(−(−3))
Step 3.4.7.2
Add 1818 and 11.
32+1+2(-192)2⋅4+2(-(-3))32+1+2(−192)2⋅4+2(−(−3))
32+1+2(-192)2⋅4+2(-(-3))32+1+2(−192)2⋅4+2(−(−3))
Step 3.4.8
Cancel the common factor of 22.
Step 3.4.8.1
Move the leading negative in -192−192 into the numerator.
32+1+2(-192)2⋅4+2(-(-3))32+1+2(−192)2⋅4+2(−(−3))
Step 3.4.8.2
Cancel the common factor.
32+1+2(-192)2⋅4+2(-(-3))32+1+2(−192)2⋅4+2(−(−3))
Step 3.4.8.3
Rewrite the expression.
32+1-192⋅4+2(-(-3))32+1−192⋅4+2(−(−3))
32+1-192⋅4+2(-(-3))32+1−192⋅4+2(−(−3))
Step 3.4.9
Add 3232 and 11.
33-192⋅4+2(-(-3))33−192⋅4+2(−(−3))
Step 3.4.10
Subtract 1919 from 3333.
142⋅4+2(-(-3))142⋅4+2(−(−3))
142⋅4+2(-(-3))142⋅4+2(−(−3))
Step 3.5
Simplify the denominator.
Step 3.5.1
Multiply 22 by 44.
148+2(-(-3))148+2(−(−3))
Step 3.5.2
Multiply 2(-(-3))2(−(−3)).
Step 3.5.2.1
Multiply -1−1 by -3−3.
148+2⋅3148+2⋅3
Step 3.5.2.2
Multiply 22 by 33.
148+6148+6
148+6148+6
Step 3.5.3
Add 88 and 66.
14141414
14141414
Step 3.6
Divide 1414 by 1414.
11
11