Question

PLEASE HELP ME AND WILL GIVE MEDAL!
2. Justify each step of the proof.

Conjecture: If 2(x2 + 5) = 60, then x is 5 or –5.

1. 2(x2 + 5) = 60 1.

2. 2x2 + 10 = 60 2.

3. 2x2 = 50 3.

4. x2 = 25 4.

5. x = ±5 5.

Answer 1

@cram

Answer 2

@Nurali pls help anyone

Answer 3

>> There's no justification needed for step 1;
>> Step 2 is true because of the distribuitive property of multiplication:
>> 2x^2 + 10 is the same as 2(x^2 + 5)
>> Step 3 is true because of the commutative property of addition, and the
>> existence of a right identity for addition: effectively, you've added -10 to
>> both sides, as in 2^2 + 10 - 10 = 60 - 10 giving 2^2 = 50
>> Step 4 is justified by the commutative property of multiplication; you're
>> multiplying each side of the equation by 1/2
>> Step 5 is justified by the argument that no other number quite fits.

Answer 4

Thank you :)

Answer 5

@Nurali did you get my pm?

Answer 6

Anytime.