How do i solve this equation using the quadratic formula: x2 – 7x – 1 = -7?

Question

How do i solve this equation using the quadratic formula: x2 – 7x – 1 = -7?

Answer 1

The quadratic equation is for equations in the form

Ax^2 + Bx + C = 0

So, you need to change the equation by adding 7 to each side

x^2 - 7x +6 = 0

Now, you can use the quadratic equation

( -b +- sqrt(b^2 - 4ac)) / 2a

where

a = 1

b = -7

c = 6

(7 +- sqrt(49 - 24) ) /2

(7 +- sqrt(25) ) /2

(7 +- 5) / 2

so...

2/2 or 12/2

finally

x = 1 or x = 6

Plug these answers back into the original equation...

1^2 - 7*1 - 1 = -7

1 - 7 - 1 = -7

-7 = -7 CHECK

----

6^2 - 7*6 - 1 = -7

36 - 42 - 1 = -7

7 = -7 CHECK

So your answer is...

x = 1 or x = 6

Answer 2

x^2 – 7x – 1 = -7

x^2 - 7x - 1 + 7 = 0

x^2 - 7x + 6 = 0

Factorize,

(x-1)(x-6) = 0

x - 1 = 0, x = 1

x - 6 = 0, x = 6

Answer: x = 1 or 6

Answer 3

(x-6)(x-1)

x= 1,6

Answer 4

add seven to both sides so you have

x2-7x-1+7=-7+7

x2-7x+6=0

x2-6x-1x+6=0

x(x-6)-1(x-6)=0

(x-6)(x-1)

therefore,x=+6or+1

Answer 5

clean this up by adding 7 to both sides.

You shd be able to see the factorisation (x-1)(x-6)=0

When is this true ? when x = 1 or x=6

Answer 6

x² - 7x + 6 = 0

x = [ 7 ± √ (49 - 24 ) ] / 2

x = [ 7 ± √ (25) ] / 2

x = [ 7 ± 5 ] / 2

x = 6 , x = 1

OR

(x - 6)(x - 1) = 0

x = 6 , x = 1