It would take 70,000 seeds if five out of seven are good. So over a quantity of 50,000 plants desired, you would sow 70,000 seeds. As 20,000 would statistically fail.
Discriminant = b^2 - 4ac, where a, b and c come from the form of the quadratic equation as ax^2 + bx + c
Discriminant = (4)^2 - 4(1)(5)
= 16 - 20
= -4
-4 < 0, therefor there are no roots
(If the discriminant = 0, then there is one root
If the discriminant > 0, there are two roots, and if it is a perfect square (eg. 4, 9, 16, etc.) then there are two rational roots
If the discriminant < 0, there are no roots)
Answer:

Step-by-step explanation:
$1800 is spent on a washing machine. This number never changes, so we just need to add that to our annual total
$89 is spent every year. This means that this number needs to be with our variable, x, as it is dependent on the number of years that occur. When we put these two things together, we get the following equation:

Answer:
see below for a graph
Step-by-step explanation:
Completing the square for x and y terms can help you put this in the standard form.
(x^2 +10x) +(y^2 +6y) = -18
(x^2 +10x +25) +(y^2 +6x +9) = -18 +25 +9 . . . . add square of half linear coefficient
(x +5)^2 +(y +3)^2 = 16 . . . . . . . circle centered at (-5, -3) with radius 4