<h3><u>Answer</u> :</h3>
Given equation : 3x² - 4 = 2x
We have to find discriminant of the equation 
⭆ 3x² - 4 = 2x
⭆ 3x² - 2x - 4 = 0
By comparing this equation with ax²+bx+c, we get
Discriminant (D) = b² - 4ac
⭆ D = (-2)² - 4(3)(-4)
⭆ D = 4 + 48
⭆<u> D = 52</u>
<h3>
Hope It Helps!</h3>
Answer:

Step-by-step explanation:

basically we want to get rid of the √3 on the denominator
to do so we multiply it by itself so it is a perfect square
but whatever we do to the top we must do to the bottom so we multiply the numerator and denominator by √3

notes : √3 × √3 = √9 which is a perfect square that simplfies to 3
Let the length be x so 4x+7x=10x=42 as it is the perimeter.
so 21x =42 x=2
lengths are 8 cms , 14 cms and 20 cms
Then you can calculate it by doing
(10/20) × 100%
The answer is 50%
So Janet spelled 50% of them correctly
Hope I can help you :)
Brainliest answer? :)