x^2-49=0 solve using quadratic formula

Question

x^2-49=0 I know the answer is 7,-7 but I am not able to get that. please show me the steps so I can see what I am missing thank you

Answer 1

x^2-49=0 I know the answer is 7,-7 but I am not able to get that. please show me the steps so I can see what I am missing thank you

 

x2 - 49 = 0

 

Easiest solution:

 

x² = 49                 [Add 49 to both sides]

 

√x² = √49            [Take the square root of both sides]

 

x = ±7

 

Using quadratic formula:

 

-(b/2a)±[b²-4ac]^1/2/2a    [for ax²+bx+c=0]

 

Your equation is (1)x² + (0)x + (-49) = 0

 

so a=1, b=0, c=-49.  Plugging them into the quadratic formula:

 

-(0/2)±[0²-4(1)(-49)]^1/2/2

 

0 ± [4*49]^1/2/2

 

± (2*7)/2

 

x = ±7