Even more algebra help!?

Question

Which of he following number sentences are true? In each case, explain how you could answer without any calculation. Check your answers by doing indicated calculations.
A: 20 x 410 = (20 x 410) + (20 x 10)
B: 20 x 308 = (20 x 340) - (20 x 32)
C: -20 x -800 = ( -20 x -1,000) + ( -20 x 200)
D: -20 + (300 x 32) = (-20 + 300) x (-20 + 32)

Answer 1

The correct answer is b.

you are basically setting up an equation that is equal to the other side.

20 x 308 is the same as 20 x (340-32)

20 x 308 = 20 x 308

6160 = 6160

c is also correct

-20 x -800 would make a positive 16000
The other side is 20000 + (-400) = 16000

Remember when multiplying, 2 negatives equal a positive, but a negative and a positive will equal a negative.

Answer 2

A: 20 x 410 = (20 x 400) + (20 x 10)

B: 20 x 308 = (20 x 340) - (20 x 32)
=20(340-32)
C: -20 x -800 = ( -20 x -1,000) + ( -20 x 200)
= -20 (-1000+200)

D: -20 + (300 x 32) = -20+(9600)

so the answers are b.c

Answer 3

A: 20 x 410 = (20 x 410) + (20 x 10)
8200 = 8200 + 200
False
You could answer without doing calcuations by observing the equation is
20x = 20x + 20y; where y isn't zero
0 = 20y; contradiction

B: 20 x 308 = (20 x 340) - (20 x 32)
6160 = 6800 - 640
True
You could do without calcuation as follows:
20x340 - 20x32 = 20x(340-32) = 20x308

C: -20 x -800 = ( -20 x -1,000) + ( -20 x 200)
True, same reason

D: -20 + (300 x 32) = (-20 + 300) x (-20 + 32)
False
-20 x (300 + 32) = (-20 + 300) x (-20 + 32) would be true

Answer 4

B- 20 X 308 = 6160

20 X 340= 6800
20 X 32 = 640
6800- 640 = 6160

Answer 5

Im pretty sure its B and C -_-
B because you're doing 20(340-32) which is 20x308.

C because you're doing the same thing as B, same way just with different numbers.

Answer 6

I'm thinking B because all the others have an error in it

Answer 7

this is not a question. you need to do your own homework. this is not what this website was made for. worse yet it appears as though u probably know how to do this.

Answer 8

cant be A