college algebra

Question

Question 4
What the equation of the line passing through (-1, 4) and parallel to y = 2x + 1?

 

Question 5
What is the equation of a line through (-1, 4) and (-2, 7)?

 

Question 6
The half-life of carbon 14 is 5,730 years. Approximately, how old is a bone that has 70% of its original carbon 14?

Answer 1

4>

2=(y-4)/(x+1)...I will leave it to you to put into slope-intercept form.

 

5>

(4-7)/(-1-(-2)=(y-7)/(x-4)...I will leave it to you to put into slope-intercept form.

 

^

6>

e^(-t/5730)=.7

-t/5730=ln (.7)

You should be able to take it from there.

 

Answer 2

4)    

      M=2 ; (-1,4)

 

     B = y - mx = 4 - 2 (-1)

                      = 4 + 2

                      = 6

 

    y = 2x + 6

 

 

5)   M = (7 - 4)/(-2 - (-1))

 

          = 3 / (-1)

 

          = -3

 

     Using (-1,4),  B = y - mx

                            = 4 - (-3)(-1)

                            = 4 - 3

                            = 1

 

          y = -3x + 1

 

 

 

 

6)       0.7C =  C * (1/2)^t/5730

 

          0.7 = (1/2)^(t/5730)

 

          ln ( 0.7) = (t/5730) ln (1/2)

 

          ln ( 0.7) / ln (1/2) = t / 5730

 

          -5730 * ln  0.7 / ln 2  = t

 

           t = 2948.5