Help with a math problem (slope)?

Question

A linear function, f, has a slope of -2. f(1) = 2 and f(2) = q. Find q.

please explain everything and any formulas that you used. thanks (:

Answer 1

using the slope formula

                    m=(q-2)/(2-1)=-2

                     m=(q-2)/1=-2

                      q-2=-2

                       q=0

Answer 2

The general linear equation is f(x) = mx + b, m is the slope. Since m = -2,

f(x) = -2x + b

f(1) = 2 = -2(1) + b

2 = -2 + b

4 = b

Therefore to comlete the linear equation,

f(x) = -2x + 4

f(2) = q

To solve q,

q = f(2) = -2(2) + 4 = 0

Answer 3

this is a really simple problem. the only formula you need is the definition of the slope = rise divided by run. that is, m (slope) = (y2 - y1)/(x2 - x1). you're two points are (1,2) and (2, q). so, using this formula, plug in (2 - q)/ (1-2) = -2. So for q, so, (2 - q) = -2 (-1)

So, 2 - q = + 2, which means 2 - 2 = +q = 0. I guarantee you q = 0.

edit = to the idiot who keeps giving everyone contributing correct answers a thumbs down, why don't you contribute something you d**k!

Answer 4

By definition the slope m is defined as follows:

............y2 - y1

.....m = -----------

............x2 - x1

We know that when x is 1, y is 2, and that when x is 2 y = q.

Hence, as the slope is -2 the above equation becomes:

............q - 2

....-2 =  --------  ....... = q - 2        as 2 - 1 = 1

............2 - 1

From here things are relatively easy

-2 = q - 2

Add 2 to both sides

0 = q

q = 0   <<<<<   (I checked the answer and it is correct.)

Answer 5

Okay, a linear function is of the form y = mx + b, where m is the slope, and b is the y intercept.

Your function has a slope of -2, so it will be y = -2x + b.  

We can use your first given value to find b by plugging in the value given, thus:

f(1) = 2 means when x is 1, y is 2.

y = -2x + b

2 = -2(1) + b

2 = -2 + b

add 2 to each side

b = 4

Now you have your linear formula by plugging b back in:

y = -2x + 4

You can now use your second given to find q.  

f(2) = q is the same as saying when x = 1, y = q.  So:

q = -2(2) + 4

Simplifying:

q = -4 + 4

q = 0

Good luck!

Answer 6

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