Help please

box 1, 4 and 5 are correct

Step-by-step explanation:

Box 1 is correct if you simplify the equation by multiplying both sides by 4.  When you multiply the left side by 4 you end up with 56 + 8x since 4 times equals 1.  The right side becomes 4 x 20 = 80.  So 56 + 8X = 80.  If you continue to solve for X, you first have to subtract 56 from both sides of the equal sign which looks like this:  56 - 56 + 8X = 80 - 56 which reduces down to 8X = 24.  Dividing both sides by 8 then reduces that equation down to X = 3.

Box 4 is also correct.  When you have an equation like (8x + 56), you have to multiple both numbers on the inside of the parentheses by the number on the outside of the parentheses.  So the equation is ( X 8x) + ( X 56) which results in 2x + 14.  The right side of the equal sign does not change so now you have

2x + 14 = 20.  To get rid of the 14 on the left, you subtract 14 from both sides.

2x + 14 - 14 = 20 - 14.  On the left, 14-14=0 so you end up with just 2x.  On the right 20-14=6.  So now you have the equation 2x = 6.  If you continue to solve for x, you divide both sides of the equal sign by 2.  This will give you x = 3.  Same as what you get by solving for x in Box 1 above.

Box 5 is also correct.  As you see above when you solve for X in both answers above, X = 3.

10.416 m/s

step-by-step explantion:

distance=100m

time= 9.6s

average speed=100/9.6

=10.416 m/s

the radius is 2 times the diameter.

step-by-step explanation: