Day: October 25, 2018

Week 7 Precalc

rubeng2016 on

In math, we learned how to solve a quadratic equation using the quadratic formula

x=\frac {-(b)\pm \sqrt {(b)^2-4(a)(c)}}{2a}

This method of solving will be used to solve the equation:

(2x+1)^2+4=49

before you can use the formula you first have to expand and make the right side of the equation equal zero

(2x+1)(2x+1)+4-49=0

Then foil and collect like terms

4x^2+2x+2x+1-45=0

 

4x^2+4x+1-45=0

 

4x^2+4x-44=0

from this point, you can look for a common factor to take out in order to make the equation easier. in this case, the common factor is four

x^2+x-11=0

Now you are able to use the quadratic formula to solve

A=1

B=1

C=-11

x=\frac{-(1)\pm \sqrt{(1)^2-4(1)(-11)}}{2}

 

x=\frac{-1\pm \sqrt{1+44}}{2}

 

x=\frac{-1\pm \sqrt{45}}{2}

 

x=\frac{-1\pm 3\sqrt{5}}{2}

 

Week 8- precalc 11

rubeng2016 on

This week in pre-cal we learned how to read an equation and determine the vertical and horizontal translations, and also how to determine whether it is a stretch, compression and/or a reflection

In the function  y=-4(x+3)+5

you can determine that the vertex is (-3,5), that is is a stretch and a reflection over the x-axis, and that the stretch is congruent to 4,12,20. the line of symmetry is -3

this was vertex is determined by the 3 and the 5 in the function above, the sign in front of the number in the brackets is the opposite to find the vertex. You determine whether or not it is a reflection by the coefficient in front of the brackets. If the coefficient is negative then it is a reflection, if it is positive it opens up. the stretch is determined by the coefficient as well if it is a whole number the parabola narrows as the number gets bigger. if the number is less than one the parabola compresses