Question

practice
what is the y-intercept of each function?
see example 1

1. $f(x) = 2x^2 - 4x - 6$ 16. $f(x) = 0.3x^2 + 0.6x - 0.7$
2. $f(x) = -2x^2 - 8x - 7$ 18. $f(x) = 3x^2 + 6x + 5$
3. $f(x) = -x^2 - 2x + 3$ 20. $f(x) = -0.5x^2 + x + 2$

Explanation:

Step1: Recall y-intercept definition

The y-intercept of a function $f(x)$ is the value of $f(0)$, found by substituting $x=0$ into the function.

Step2: Solve for problem 15

Substitute $x=0$ into $f(x)=2x^2-4x-6$:
$f(0)=2(0)^2 - 4(0) - 6 = -6$

Step3: Solve for problem 16

Substitute $x=0$ into $f(x)=0.3x^2+0.6x-0.7$:
$f(0)=0.3(0)^2 + 0.6(0) - 0.7 = -0.7$

Step4: Solve for problem 17

Substitute $x=0$ into $f(x)=-2x^2-8x-7$:
$f(0)=-2(0)^2 - 8(0) - 7 = -7$

Step5: Solve for problem 18

Substitute $x=0$ into $f(x)=3x^2+6x+5$:
$f(0)=3(0)^2 + 6(0) + 5 = 5$

Step6: Solve for problem 19

Substitute $x=0$ into $f(x)=-x^2-2x+3$:
$f(0)=-(0)^2 - 2(0) + 3 = 3$

Step7: Solve for problem 20

Substitute $x=0$ into $f(x)=-0.5x^2+x+2$:
$f(0)=-0.5(0)^2 + (0) + 2 = 2$

Answer:

1. $\boldsymbol{-6}$
2. $\boldsymbol{-0.7}$
3. $\boldsymbol{-7}$
4. $\boldsymbol{5}$
5. $\boldsymbol{3}$
6. $\boldsymbol{2}$