Question

2.2 When we simplify surds. we often leave a square-root or cube-root in the denominator. However, the calculator rationalizes the answer so that there is no surd in the denominator. With that said. rationalise and also solve for x in the following: √√√4 + x = 3 3 1-√2 b.​

Answer 1

a. To rationalize the expression √√√4 + x = 3 3, we need to get rid of the cube roots in the denominator.

First, we simplify the cube root of 4:

√√√4 = √√2

So, our expression becomes:

√√2 + x = 3 3

To get rid of the cube root in the denominator, we need to multiply both sides by the conjugate of the denominator:

(3 - √2)(√√2 + x) = 3

Expanding the left side:

3√√2 + 3x - 2√2 - √2√√2x = 3

Simplifying:

3x - 2√2 - √2√√2x = 3 - 3√√2

Combining like terms:

(3 - √2)x = 3 - 3√√2 + 2√2

Simplifying:

(3 - √2)x = (3 + 2√2) - 3√√2

Dividing both sides by (3 - √2):

x = [(3 + 2√2) - 3√√2]/(3 - √2)

Simplifying:

x = (3 + 2√2)(3 + √2)/7

b. To rationalize and solve for x in the expression 1-√2:

We need to get rid of the radical in the denominator by multiplying both the numerator and denominator by its conjugate:

1 - √2 / 1 - √2 * 1 + √2 / 1 + √2

Simplifying, we get:

(1 - √2)(1 + √2) / (1 - √2)(1 + √2)

= 1 - 2

= -1

So, x = -1.

Therefore, the rationalized expressions are:

a. √√2 + x = (3 + 2√2)(3 + √2)/7

b. 1-√2 = -1