NightowlIt can be proven that between any two real numbers there exists a rational number. Therefore there exists a rational number r such that
<span>7.7+<span>2–√</span><r<7.9+<span>2–√</span></span>By calculator we can find a rational number r that satisfies these condition, I choose 9.2. Now subtract square root 2.<span>7.7<9.2−<span>2–√</span><7.9
</span>so the answer is between 7.7 and 7.9
rational number : 7.8
<span>irrational number : 9.2 - √2</span>
Solving for a variable in an equation means, we are changing the subject of formula of the equation.
The equation of r is: 
The equation is given as:

We start by multiplying both sides by 3

Rewrite as:

Divide both sides by 

Cancel out common factors

Take square roots of both sides

Evaluate the right-hand sides

Make r the subject

Hence, the resulting equating for r is:

Read more about the subject of formulas at:
brainly.com/question/21866313
What are you trying to find? y?x?..???