Let S be the amount in a savings account.
Let m be the number of months.
General equation
S = 132 + 27m
Specific question
July is the 7th month of the year including both January and July.
S = 132 + 7*27
S = 132 + 189
S = 321
Reasonableness?
Good question. You could estimate an answer.
Start with 150 dollars and say that you add 25 a month.
7 * 25 = 175
S = 150 + 175 = 325 All of this was done in my head. Since the exact answer obtained using the formula is 321, I think that's pretty reasonable using my estimate is a guide.
What do you mean by in words?
To eliminate the fraction, multiply by 2 both sides of the equation. This gives,
2A = h x (b1 + b2)
Then, divide both the left hand and the right hand side of the equation by the variable h.
2A / h = b1 + b2
Next, subtract b1 from both sides,
(2A / h) - b1 = b2
Rearranging the equation,
b2 = (2A/h) - b1
-3 × -5 = -15
-15 × 0 = 0
