Answer:
21
Step-by-step explanation:
y+9 = ?
y=12
12+9=21
Check the picture below. So let's use those two points on the line.

bearing in mind that the standard form is also a general form.
standard form for a linear equation means
• all coefficients must be integers, no fractions
• only the constant on the right-hand-side
• all variables on the left-hand-side, sorted
• "x" must not have a negative coefficient
Answer:
To multiply rational expressions, first factor all numerators and denominators and cancel any factors you can. Then multiply what you have left.
Step-by-step explanation: