Answer:
how long is the shelf
Step-by-step explanation:
Answer: She has 40 nickels and 40 quarters .
Step-by-step explanation:
Let be "n" the number of nickels Theresa has and "q" the number of quarters Theresa has.
You know that she has a total of $12 in nickels and quarters. In cents, this is:

Then, based on this you can write the following expression:

Since
, you can rewrite it as:

Solving for "n", you get:

Therefore she has 40 nickels and 40 quarters .
3b=y+3x
To solve for B you need to put B before the equals sign
Answer:
x = 4 , y = -1
Step-by-step explanation:
x - 3y = 7 -- (1)
3x - 3y = 15 -- (2)
Rewriting (1), x = 3y + 7 -- (1)'
Substituting (1)' into (2),
3 ( 3y + 7 ) - 3y = 15
9y + 21 - 3y = 15
6y = -6
y = -1 -- (3)
Substituting (3) into (1),
x - 3 ( - 1 ) = 7
x + 3 = 7
x = 4 -- (4)
According to (3) and (4),
x = 4 , y = -1