The addition property of equality justifies this. You could also say that she simply subtracted 7, and then it would be the subtraction property of equality. This is the case because if you add or subtract (or multiply or divide) the same number on both sides of an equation, the equation will still be the same.
Hope it helps!
Answer:
a = x² + 3x - 40
Step-by-step explanation:
a = l * w
a = (x - 5)(x + 8)
a = x(x + 8) - 5(x + 8)
a = (x² + 8x) + (- 5x - 40)
a = x² + 3x - 40
f + 6 = ?
Well, the answer can be pretty much any number. It all depends on what number f is. f is a variable, so you can plug in any number to replace f.
For example, if f was 5, this is what the equation would look like:
5 + 6 = 11
If f was -3, this is what the equation would look like:
-3 + 6 = 3
So, again, the answer can be anything. It depends on what f is.
