Math  /  Algebra

Question(1 point) Given the function f(x)=28x+8f(x)=-2 \sqrt{8-x}+8 The yy-intercept of the function is \square The xx-intercept of the function is \square help (points) After submitting an answer, you can get a hint and click "Show Me Another" to see a simila

Studdy Solution

STEP 1

What is this asking? We need to find the points where this curvy function f(x)f(x) crosses the x-axis and the y-axis! Watch out! Remember that the y-intercept happens when x=0x = 0 and the x-intercept happens when y=0y = 0, so don't mix them up!

STEP 2

1. Find the y-intercept
2. Find the x-intercept

STEP 3

To find the y-intercept, we need to figure out where the function crosses the y-axis.
This happens when x=0x = 0.
So, let's **substitute** x=0x = 0 into our function f(x)f(x).

STEP 4

f(0)=280+8 f(0) = -2 \cdot \sqrt{8 - 0} + 8 f(0)=28+8 f(0) = -2 \cdot \sqrt{8} + 8

STEP 5

We can simplify 8\sqrt{8} by noticing that 8=428 = 4 \cdot 2, so 8=42=42=22\sqrt{8} = \sqrt{4 \cdot 2} = \sqrt{4} \cdot \sqrt{2} = 2\sqrt{2}.
Let's **plug that in**: f(0)=222+8 f(0) = -2 \cdot 2\sqrt{2} + 8 f(0)=42+8 f(0) = -4\sqrt{2} + 8

STEP 6

So, our **y-intercept** is (0,42+8)(0, -4\sqrt{2} + 8)!

STEP 7

Now, for the x-intercept!
This is where our function crosses the x-axis, meaning f(x)=0f(x) = 0, or y=0y = 0.
Let's **set** our function equal to zero and **solve for** xx: 0=28x+8 0 = -2\sqrt{8 - x} + 8

STEP 8

First, let's **isolate** the square root term.
We can do this by **subtracting** 8 from both sides: 8=28x -8 = -2\sqrt{8 - x}

STEP 9

Now, let's **divide** both sides by -2: 82=28x2 \frac{-8}{-2} = \frac{-2\sqrt{8 - x}}{-2} 4=8x 4 = \sqrt{8 - x}

STEP 10

To get rid of the square root, we can **square** both sides: 42=(8x)2 4^2 = (\sqrt{8 - x})^2 16=8x 16 = 8 - x

STEP 11

Now, we can **solve for** xx.
Let's **subtract** 8 from both sides: 168=8x8 16 - 8 = 8 - x - 8 8=x 8 = -x

STEP 12

Finally, **multiply** both sides by -1 to get: 8=x -8 = x x=8 x = -8

STEP 13

So, our **x-intercept** is (8,0)(-8, 0)!

STEP 14

The y-intercept is (0,42+8)(0, -4\sqrt{2} + 8). The x-intercept is (8,0)(-8, 0).

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