Question

Find the value of x in x^2 + 1 = 4

Answer 1

Answer:

Solve the first equation for x and then substitute the answer into the second. The first equation can be rewritten as x^2 - 4x + 1 = 0. This doesn't have integer solutions so write it as (x-2)^2 = 3 so x = 2 - sqrt(3) or x = 2 + sqrt(3). Now cube these: 8 - 12 sqrt(3) + 18 - 3 sqrt(3) or 8 + 12 sqrt(3) + 18 + 3 sqrt(3). Simplify these and substitute into the second expression. Please make sure you understand how I got these.

Although this gives both answers it will be more elegant if you rationalise the fraction in the second term so the whole answer is of the form a + b sqrt(3). (Remember how to do this: 1/(p+q sqrt(c)) = (p-q sqrt(c))/(p^2 - q^2 c).)

Step-by-step explanation:

hope it will help you if correct please mark me as brainliest

Answer 2

x^2 +1 = 4

x^2 = 4-1 = 3x

x = Root3