It is b + 9.
The reciprocal of any number or expression is one divided by that number or expression. In this case, you can also write -x + 3 as 3 - x; the reciprocal would be 1 / (3 - x). The parentheses are necessary, to indicate that you want to divide 1 by the entire expression. But if you write it in fraction form, with "3 - x" on the bottom, no parentheses are required.
Without parentheses, the expression is way too ambiguous.
You can expand the first expression in parentheses, then add or subtract like terms.
It is: 3n-21+4n+8 = 7n-13 simplified
3(10x + y) + 2x + 7y (multiply the 3 through the parentheses then combine like terms) = 30x + 3y + 2x + 7y = 32x + 10 y Evaluate an expression for some values of x and y, means to substitute those values into the expression, such that when x = 3 and y = 1 the value of the given expression is 106: 32x + 10y = 32(3) + 10(1) = 96 + 10 = 106
3(x+12), where the parentheses state that you must do the addition first.
3(2y + 3)(y + 2)
Three and eight times a number.
(x + 5) + 3
5x+3
2x+3
It is a numerical expression.