EXPLANATION
Let's call x to the square:
The first equation is:
[tex]\frac{4}{5}\cdot x=28[/tex]
We need to isolate x, how can we do it?
Multiplying both sides by 5/4:
[tex]\frac{4}{5}\cdot\frac{5}{4}\cdot x=28\cdot\frac{5}{4}[/tex]
Multiplying the numerators:
[tex]x=\frac{140}{4}[/tex]
Simplifying the fraction:
[tex]x=35[/tex]
The solution is 35
In the second equation:
[tex]\frac{3}{10}\cdot x=\frac{57}{10}[/tex]
Multiplying both sides by 10/3:
[tex]x=\frac{10}{3}\cdot\frac{57}{10}=[/tex]
Multiplying terms:
[tex]x=\frac{570}{30}[/tex]
Simplifying:
[tex]x=19[/tex]
The solution is 19
In the third equation:
[tex]\frac{5}{9}\cdot x=15[/tex]
Multiplying both sides by 9/5:
[tex]x=\frac{9}{5}\cdot15[/tex]
Multiplying numerators and denominators:
[tex]x=\frac{135}{5}[/tex]
Simplifying:
[tex]x=27[/tex]
In the fourth equation:
[tex]\frac{3}{16}\cdot x=\frac{63}{16}[/tex]
Multiplying both sides by 16/3:
[tex]x=\frac{63}{16}\cdot\frac{16}{3}[/tex]
Multiplying terms:
[tex]x=\frac{1008}{48}[/tex]
Simplifying:
[tex]x=21[/tex]
The solution is 21
