Answer:
9
Step-by-step explanation:
9v = 9(2i + 9j) = 18i + 81j
|9v | = 
= 
= 9
Answer:
there is nothing to prove
Step-by-step explanation:
Answer:
two real, unequal roots
Step-by-step explanation:
y is definied as y = 3x - 1. Substitute 3x - 1 for y in xy = 9, obtaining:
x(3x - 1) = 9. Then:
3x^2 - x - 9 = 0. In this quadratic, the coefficients are a = 3, b = -1 and c = -9.
Calculating the discriminant b^2 - 4ac, we get (-1)^2 - 4(3)(-9), or 1 + 108, or 109. Because the discriminant is positive, we have two real, unequal roots.
We define variables:
x = represent the width of the field
y = represent the length of the field
We write the perimeter (with no fencing along the river):
2400 = 2x + y
We clear y:
y = 2400-2x
Answer:
an expression for the length of the field as a function of x is:
y = 2400-2x
