Question

What are the solutions to the quadratic equation x^2=7x+4

Answer 1

x = 7/2 ±sqrt(65)/ 2

Explanation:

x^2=7x+4

Subtract 7x from each side

x^2-7x=7x-7x+4

x^2 -7x =4

Complete the square

Take the coefficient of x and divide by 2

-7/2

Then square it

(-7/2)^2 = 49/4

Add this to each side

x^2 -7x +49/4 =4+49/4

(x-7/2)^2 = 4 +49/4

(x-7/2)^2 = 16/4 +49/4

(x-7/2)^2 =65/4

Take the square root of each side

sqrt((x-7/2)^2) =±sqrt(65/4)

x-7/2 = ±sqrt(65)/ sqrt(4)

x-7/2 = ±sqrt(65)/ 2

Add 7/2 to each side

x-7/2 +7/2=7/2 ±sqrt(65)/ 2

x = 7/2 ±sqrt(65)/ 2