Assume E represents the cost of an egg and T represents the cost of one piece of toast.
We can construct two equations :
2E + T = $3.00 - - - - - (a)
E + T = $1.80 - - - - - (b)
Subtract equation b from a:
E = $1.20 (The price of one egg)
To find out the price of one piece of toast, replace the price of one egg in equation b:
T = $1.80 - $1.20 = $0.60 (The price of one piece of toast)
Hope that helps you
Answer:
d) 
because that would be the same as 
bisector. Base. In geometry, the base of a shape is the side (usually the bottom) that forms a right (90 degree) angle with the height of the object. Biannual.
