Someone Please help me answer this question

∠ QRS = 43°

Step-by-step explanation:

The sum of the 3 angles in a triangle = 180°

Sum the 3 angles and equate to 180

4n - 9 + 5n - 18 + 90 = 180, that is

9n + 63 = 180 ( subtract 63 from both sides )

9n = 117 ( divide both sides by 9 )

n = 13

Thus

∠ QRS = 4n - 9 = 4(13) - 9 = 52 - 9 = 43°

∠ RSQ = 4n - 18 = 4(13) - 18 = 65 - 18 = 47°

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.

29933333.33

step-by-step explanation: