Question

Solve Ax + By = C for x.

1. x equals the quantity negative B times y plus C all over A
2. x equals the quantity B times y plus C all over A
3. x equals the quantity B times y minus C all over A
4. x equals the quantity negative B times y minus C all over A

Answer 1

x equals the quantity negative B times y plus C all over A

Explanation:

First I like to translate the words into the actual equations they represent...

• "equals" means use the =
• the phrase "the quantity of..." usually means parentheses are involved
• "negative" means -
• "times" means multiply. There usually isn't an actual multiplication sign. for example "3 times x" would be written as 3x
• plus means add (+)
• "all over ___" would mean that the first part is the numerator of a fraction and whatever is in the blank would be the denominator

so...

1. x = (-By + C) / A

2. x = (By + C) / A

3. x = (By - C) / A

4. x = (-By - C) / A

To solve:

starting equation is

Ax + By = C

so to get x by itself you first subtract By from both sides of the equation

Ax = -By + C

and then divide by A

x = (-By + C) / A

which matches the first answer