Math  /  Algebra

Question6. 1. Evaluate the following for f(x)={3x5,x2x2,x<2f(x)=\left\{\begin{array}{cc}3 x-5, & x \geq 2 \\ x^{2}, & x<2\end{array}\right. a) f(5)f(-5) b) f(2)f(2) c) f(5)f(5)

Studdy Solution

STEP 1

What is this asking? We're given a *piecewise function* f(x)f(x), which means it acts differently depending on the input xx, and we need to find its value at three different xx values: 5-5, 22, and 55. Watch out! Make sure to plug each xx value into the *correct piece* of the function!
The conditions tell you which formula to use.

STEP 2

1. Evaluate f(5)f(-5)
2. Evaluate f(2)f(2)
3. Evaluate f(5)f(5)

STEP 3

Alright, let's **start** with f(5)f(-5)!
Since 5-5 is *less than* 22, we'll use the second formula: f(x)=x2f(x) = x^2.

STEP 4

**Substitute** 5-5 for xx: f(5)=(5)2f(-5) = (-5)^2

STEP 5

**Calculate** the square: f(5)=(5)(5)=25f(-5) = (-5) \cdot (-5) = 25 So, f(5)=25f(-5) = \textbf{25}!

STEP 6

Next up, f(2)f(2)!
Since 22 is *greater than or equal to* 22, we use the *first* formula: f(x)=3x5f(x) = 3x - 5.

STEP 7

**Substitute** 22 for xx: f(2)=3(2)5f(2) = 3 \cdot (2) - 5

STEP 8

**Multiply**, then **subtract**: f(2)=65=1f(2) = 6 - 5 = 1 So, f(2)=1f(2) = \textbf{1}!

STEP 9

Finally, let's find f(5)f(5)!
Since 55 is *greater than* 22, we use the *first* formula *again*: f(x)=3x5f(x) = 3x - 5.

STEP 10

**Substitute** 55 for xx: f(5)=3(5)5f(5) = 3 \cdot (5) - 5

STEP 11

**Multiply**, then **subtract**: f(5)=155=10f(5) = 15 - 5 = 10 Therefore, f(5)=10f(5) = \textbf{10}!

STEP 12

f(5)=25f(-5) = 25, f(2)=1f(2) = 1, and f(5)=10f(5) = 10.
We've conquered the piecewise function!

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