Answer:
x = 3
Step-by-step explanation:
![\begin{array}{rcll }\dfrac{x}{8} & = & \dfrac{7.5}{20} &\\\\x & = & 8\times \dfrac{7.5}{20}&\text{Multiplied each side by 8}\\\\ & = & \dfrac{60}{20} & \text{Simplified}\\\\ & = & \mathbf{3} & \text{Cancelled the 20s}\\\end{array}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcll%20%7D%5Cdfrac%7Bx%7D%7B8%7D%20%26%20%3D%20%26%20%5Cdfrac%7B7.5%7D%7B20%7D%20%26%5C%5C%5C%5Cx%20%26%20%3D%20%26%208%5Ctimes%20%5Cdfrac%7B7.5%7D%7B20%7D%26%5Ctext%7BMultiplied%20each%20side%20by%208%7D%5C%5C%5C%5C%20%26%20%3D%20%26%20%5Cdfrac%7B60%7D%7B20%7D%20%26%20%5Ctext%7BSimplified%7D%5C%5C%5C%5C%20%26%20%3D%20%26%20%5Cmathbf%7B3%7D%20%26%20%5Ctext%7BCancelled%20the%2020s%7D%5C%5C%5Cend%7Barray%7D)
Check:
![\begin{array}{rcl}\dfrac{3}{8} & = & \dfrac{7.5}{20 }\\\\0.375 & = & 0.375\\\end{array}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcl%7D%5Cdfrac%7B3%7D%7B8%7D%20%26%20%3D%20%26%20%5Cdfrac%7B7.5%7D%7B20%20%7D%5C%5C%5C%5C0.375%20%26%20%3D%20%26%200.375%5C%5C%5Cend%7Barray%7D)
It checks.
Answer:
20.
m = -52
22.
x=13
24.
a=-90
26.
n=-2
28.
a=9
30.
m=-10
Step-by-step explanation:
20. m/4=-13
m = -13*4 = -52
22. -143=-11x
x=-143/-11 =13
24. -5=a/18
a=-5*18= -90
26. n-8=-10
n=--10+8
n=-2
28. a+11=20
a=20-11
a=9
30. 18+m=8
m=8-18
m=-10
13 x 8 = 1048 x 10 = 800.5 x 10 x 12 = 60
SA = 104 + 104 + 80 + 60 + 60 SA = 408 cm2
The 1st one =no
2nd: YES
3rd : NO
4th yes