Answer:

Step-by-step explanation:
Given the rhombus CDEF, sides FC and CD are adjacent sides.
Using coordinate geometry, to proof that a quadrilateral is a square, with regards to the slope, the slope of adjacent segments must be negative reciprocals.
In fact, by definition: Two lines with slopes
are perpendicular if:

Therefore if :
- FC and CD are adjacent segments
- Slope of FC=25
For the rhombus to be a square:
Slope of CD 
Answer:
A total= 0.6703125 ft²
Step-by-step explanation:
A1= 3.9× 14.3= 55.77 in²
A2=1/2 × 14.3× ( 9.6-3.9)= 40.755 in²
A total= A1+ A2= 55.77+40.755=96.525 in²
1 ft= 12 in , 1ft²= 144 in²
Atotal= 96.525÷144= 0.6703125 ft²
Answer:
The quantities used by Manuela were correct
Step-by-step explanation:
The question is
Did Manuela use the right quantities?
Let
x -----> the parts of oil
y ----> the parts of vinegar
we know that
The ratio of the parts of oil by the parts of vinegar of recipe is

Determine the relation used by Manuela

Compare with the recipe


Is true, the quantities are proportional
therefore
The quantities used by Manuela were correct
Answer:
72y2-45
Step-by-step explanation:
9y2 + 9(7y2 - 5)
you multiply the 9 by the stuff in the parentheses
9y2 + 63y2 - 45
72y2-45