It may be easier to start from
.. a(x +3)(x -1) = 0
.. a(x^2 +2x -3) = 0
The quadratic
.. ax^2 +bx +c = 0 will have solutions -3 and 1 for ...
.. a ≠ 0
.. b = 2a
.. c = -3a
Correct. They only want to know how many are 5 cm tall. So we only need to count the 'x' 's in the 5 area, which are 6. You are correct
Answer=6
√(3x+4)-3=2 add 3 to both sides
√(3x+4)=5 square both sides
3x+4=25 subtract 4 from both sides
3x=21 divide both sides by 3
x=7
36 + x would be your answer. When something is 'increased', you are adding to it. Such as saying 47 increased by -5x is the same as 47 + (-5x).
If this wasn't the answer you were looking for, let me know. For now, I hope this helped:)