Solve the following equations.
20. x/4 + 10 = 3/4
21. 12 = |x + 8|
22. -3|x - 4| + 2 = -7
23. 16(x – 2) – (x – 3) = 29
24.5/6(2x – 8) = 45
25. f = 9/5c + 32 solve for c.

20

Start with

Multiply both sides by 4:

Subtract 40 from both sides:

21

If the absolute value of something equals 12, then that something is either 12 or -12: the possibilities are

or

22

You can isolate the absolute value

And proceed as before.

23

Distribute the 16:

24

Multiply both sides by 6/5:

25

Start with

Subtract 32 from both sides

Multiply both sides by 5/9

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m