Question

Maura writes an expression equivalent to 8a - (-3 - 5a) - 2a. Her work is in the picture. In what step does Maura make a mistake? Describe her error and find the correct equivalent expression.

* 8a - (-3 - 5a) -2a *

Step 1: 8a + 3 - 5a - 2a
Step 2: (8a - 5a - 2a) + 3
Step 3: (3a - 2a) + 3
Step 4: a + 3

Answer 1

11a + 3

Explanation:

Step 1 : 8a + 3 - 5a - 2a

error => - 5a

8a - (- 3 - 5a) - 2a =

= 8a + 3 + 5a - 2a

= (8a + 5a - 2a) + 3

= 11a + 3

Answer 2

11a+3

Explanation:

8a-(-3-5a)-2a

Open the bracket first

8a+3+5a-2a

Collect like terms

8a+5a-2a+3

13a-2a+3

11a+3

So the final answer is 11a+3

The error is the that when you open the bracket the minus outside the bracket will multiply everything inside the bracket...and -×-=+