Question

Help with all please ​

Answer 1

13. 68

14. y = 0.50x + 8

15. y = 25x - 15

16. y = 7x - 1

17.
`a_n = 4 + 6(n-1)`

Explanation:

13. f(3) means plug in 3 for x.

f(3) = 7(3)² + 5 = 7(9) + 5 = 63 + 5 = 68

14. Write out what you know. 0.50 inches per hour is the rate of snowfall, or your m, or your slope. m = 0.50. If x is hours passed and y is inches of snowfall, then you also know that at x = 4, y is 10. Plug these into the standard linear formula: y = mx + b => 10 = 0.50(4) + b

Solve for b:

10 = 0.50(4) + b

10 = 2 + b

b = 8

Remember, x and y are variables, not constants, but m and b are always the same for some given function. So your answer is y = 0.50x + 8

15. Write out what you know. If x is hours passed and y is distance from home in miles, then we need to find the slope and y-intercept using what you're given. How do you find the slope? Use this:
`m (or slope) = (y_2 - y_1)/(x_2 - x_1)`.

You have two points given: (3, 60) and (7, 160). So
`m = (160-60)/(7-3) = (100)/(4) = 25`

Now, just use either of these points to find b, or your y-intercept.

y = mx + b

Let's just use (3, 60); either one would work though.

`60 = 25(3) + b`

60 = 75 + b

b = -15

To make the equation, use the values for m and b that you found.

m = 25 and b = -15, so y = 25x - 15

16. In y = mx + b, b is the y-intercept, but it's also how much the graph shifts up or down from its "original" position. I don't really want to explain this, but you can experiment with y = x + something (like try y = x + 1, y = x - 1, y = x, y = x + 3) and you'll see the pattern of what I'm talking about. To move y = 7x + 3 down 4 units, just subtract 4 from 3 to get -1: you will get y = 7x - 1.

17. sorry I hope someone else gives u an explanation I'm kind of bored with these