it says simplify each expression. justify each step.
1. (2 + 7m) + 5
2. 9 x (r x 21)
1. Why not add the 5 and the 2?
2. Does the x indicate multiplication, or a variable?
I will assume it is a variable. It is better to use * instead of x when typing, for multiplication to avoid confusion.
9 x (r x 21) = (9*21)x^2*r
Multiply out the 9*21.
a+(b+2)=(b+12)+a
To simplify an expression, you need to perform the necessary mathematical operations according to the order of operations (PEMDAS/BODMAS). Here's a step-by-step explanation for each expression:
1. (2 + 7m) + 5:
Step 1: Start by simplifying the parentheses. There is a sum within the parentheses, so you can add 2 and 5.
(2 + 7m) + 5 = 7m + 7
Justification: The numbers 2 and 5 are contained within the parentheses, so we can simplify them by adding them.
Step 2: Distribute the 7m to both terms inside the parentheses.
7m + 7
Justification: The multiplication operation is implied between 7 and m, so we distribute the 7m.
2. 9 x (r x 21):
Step 1: Simplify the parentheses by performing the multiplication inside.
(r x 21) = 21r
9 x (r x 21) = 9 x 21r
Justification: Since we're multiplying r by 21, we can simplify the expression within the parentheses.
Step 2: Multiply 9 and 21r.
9 x 21r = 189r
Justification: 9 multiplied by 21 is 189, and we multiply it by r.
In both cases, we simplified the expressions by following the order of operations and combining like terms or performing the necessary operations.