how to solve these equations step by Step

Question

x²-9x+20=0

 

2x²-7=-6

Answer 1

Hello, again Britt

 

Since you don't specify the method.  I am going to solve them by factoring.

 

1)  x^2-9x+20= 0          

Find the factors 0f 20, both positive and negatives that add up to -9.  These  1,-1,2, -2, 4, -4, 5, -5, 10, -10, 20, -20.  The only two factors of 20 that addup to -9 are -4 and -5.  So, these are the values that we need to use.

  

(x-4)(x+5)=0                 Make both equal to 0

 

x-4=0 or  x+5=0

 x=4   or  x= -5    

 

2)  2X^2-7= -6                    Add 7 to both sides

              +7  +7

      2X^2= 1                        Divide both sides by 2

       x^2 = 1/2                     Take the sq. rt. of both sides

          X= =/- (.7071)

 

x= .7071 0r x= -.7071

 

 

I hope this helps out.  Take care. and keep asking questions.  Don't forget to rate my answer :)

 

D. Y. Taylor