First one is 5

Second 3×43 is 129

3×41 is 123

The difference is 6.

Expression Justification… what do you mean?

Don’t know what that is and I have taken Alg, AlgII, Trig, Geo, Calc I, II, and III and Analysis

1. +7-7 are inverse operations using the inverse property of addition. This property states that if you add a number and its inverse, the result is 0. (i.e. 3 + (-3) = 0)

2. PEMDAS – the order of operations. You can follow the standard order of operations and will get the following

5+7 = 12 12-7 = 5

Second problem

1. This problem uses the Law of Distribution which states that a*b – a*c = a*(b-c) so it can be rewritten as

3 (43-41) or 3 (2) = 6

Hope this helps

the 2nd one is 3×43-3×41. do you mean it’s 3x(43-3)x41? that would be easy. 3x40x41 is 120×41 equals 4920. simple, aye?

but if it’s 3×43 – 3×41, you could make this 3x(43-41) equals 3×2=6. even more simple, aye? this is called the distributive.