ElectricPavlov

x-y = 25     so y = x-25

x+y = 151       sub in  y = x-25

x + x -25 = 151

2x = 176

x= 88

y = x -25 = 63

x + (x-6) = 38

2x -6 = 38

2x = 44

x = 22

x-6 = 16

The area of a circle is given by     area = pi r^2

area = 121 pi  = pi r^2      Divide both sides by pi

             121 = r^2

                r= 11

See the 'Register' right next to the 'Login'   on the home screen????

You start with a quadratic of the for  ax^2 + bx + c = 0

Then you can use the Quadratic Formula to solve for 'x

\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)

Or you can soemtimes factor the quadratic equation    

Example

x^2 + 5x + 6 = 0    can easily be factored to

(x+3)(x+2) = 0     which 'solves' for x = -3 or -2

Or ....you can graph it and find where y=o for the 'zeroes' tha satisfy the equation.....

...... and you want to know the original trinomial?    Factor 4x out of the result

4x(2x^2 -x -3)         =   8x^3-12x-4x^2

SO the original was  2x^2 -x - 3

Dividing by ZERO is termed    UNDEFINED       <------ YOu cannot divide by zero

If you graph this you will have  3 points

3 hrs  ,  $30        (3,30)

5hrs       $51       (5,51)

6 hrs      61.20    (6, 61.2)

We are looking for the equation  y= mx + b

m = slope   b = y-intercept

slope =  (y2-y1) / (x2-x1)  =   (51-30) / (5-3)  = 21/2   = SLOPE    (or  10.5)

so y = 21/2  x + b      If you sub in one of the points you can find b

     30 = 21/2 (3)  + b

b=  - 1.5

CHECK:     y = 21/2 ( 6) - 1.5 = 61.50    Correct !

First, let's simplify

226 = 2 x 7 x 5    +   2 x 5 x ?    +   2 x 7 x ?

      = 70                + 10?             +   14?             Now subtract 70 from each side

156 =                        10?            + 14?             and combine 'like' terms

156 =                                  24?                        Divide both sides by 24 to find ?

6.5   =       ?

THAT is ONE set  of numbers that you can multiply together to get 3....look at that answer from yesterday......