Question

15- [(3^2+ 6) ÷5=12

my teacher told me it was 12 but idk how to do it idk the strategy
4×[50-3(1+3)^2]= 8
idk the strategy pls help ?? plzzzz​

Answer 1

The strategy to evaluate these expressions is called PEMDAS.

Explanation:

Problem #1

`15-[(3^2+6)/5]`

We're going to be following the rule of PEMDAS:

1. Parentheses
2. Exponents
3. Multiplication
4. Division
5. Addition
6. Subtraction

Keep in mind that multiplication/division and addition/subtraction are done from left to right.

In the first expression (written above), we'll first evaluate everything inside the brackets first (brackets are used when there are parentheses inside of it - but they serve the same function). There are parentheses in these brackets, so that will be the absolute first step in evaluating.

Solve for
`3^2+6` then rewrite the expression.

• 
  `15-[(15)/5]`

Now finish evaluating inside the parentheses by dividing 15 by 5.

• 
  `15-[3]`

The last step to evaluate the expression is to subtract 3 from 15.

• 12

Problem #2

`4*[50-3(1+3)^2]`

Evaluate everything inside the the brackets. Start with the parentheses since that is first according to PEMDAS. Add 1 and 3 together then rewrite the expression.

• 
  `4*[50-3(4)^2]`

Exponents are solved next after parentheses in PEMDAS, so evaluate the exponent.

• 
  `4*[50-3(16)]`

Multiplication is done before subtraction, so multiply 3 and 16 together.

• 
  `4*[50-(48)]`

Finish evaluating inside the brackets by subtracting 48 from 50.

• 
  `4*[2]`

The last step in evaluating the second expression is to multiply 4 and 2 together, which gives us 8.

• 8