He was not supposed to simplify. He could have multiplied straight across and got 12/63 and he would simplify that which would be 4/21 im thinking
Answer:

Step-by-step explanation:
→ First understand what Pythagoras theorem is
Pythagoras is a theorem used to find the hypotenuse (the side opposite to the right-angle) of a triangle. We would need the base lengths as well the height in order to use Pythagoras.
→ State the formula and identify the letters
a² + b² = c² ⇒ where 'a' is 380cm, 'b' is 290cm and 'c' is what we are trying to work out
→ Substitute in the values into the formula
380² + 290² = c²
⇒ Simplify
144400 + 84100 = c²
⇒ Collect the numbers together
228500 = c²
⇒ Square root both sides to find 'c'
478.0167361 = c
→ The length of the diagonal is 478.02
C. f(x)=2/3x-2
<h2>
Explanation:</h2>
Looking at the graph we realize that the y-intercept is given by:

The Slope-intercept form of the equation of a line is given by:

So, our equation becomes:

So the only option that matches a negative y-intercept is C. Let's see that the slope
. Look at the y-intercept, if you increase x by 3 units, then y increases by 2 units and goes from
to
. In other words:

<h2>Learn more:</h2>
Writing linear equations: brainly.com/question/12169569
#LearnWithBrainly