Question

Step

Justification

Step 1: ​2(x−4)+x5=2x+9

Given

Step 2: ​2x−8+x5=2x+9

Distributive property of multiplication over addition

Step 3: ​10x−40+x=10x+45

Commutative property of multiplication

Step 4: ​11x−40=10x+45

Associative property of addition

Step 5: ​x−40=45

Subtraction property of equality

Step 6: ​x=85

Addition property of equality

Which step of the solution has an incorrect justification?

A
Step 2

B
Step 3

C
Step 4

D
Step 5

Answer 1

Answer:

C

Step 4

Step-by-step explanation:

The given steps and justifications are:

$2(x - 4) + \frac{x}{5} = 2x + 9$

Given

Step 2

$2x - 8 + \frac{x}{5} = 2x + 9$

Distributive property of multiplication over addition

Step 3

$10x - 40 + x = 10x + 45$

Commutative property of multiplication

This justification is not correct.

This justification is not correct. This is rather the inverse property

This justification is not correct. This is rather the inverse propertyTherefore step 3 has an incorrect justification.

Step 4: 11x−40=10x+45

Associative property of addition

Step 5: x−40=45

Subtraction property of equality

Step 6: x=85

Addition property of equality