Question

x x 280 : 25 - 7,2 = 15

Answer 1

\(x\times280:25-7,2=15\\ \Rightarrow x\times11,2=22,2\\ \Rightarrow x=\dfrac{111}{56}\)

Answer 2

( x+4 ) + (x+6 ) + (x+8) + ...+(x+26) = 210

 

Answer 3

\(\Rightarrow x.280:25-7,2=15\)

\(\Rightarrow x.\left(280:25\right)=22,2\)

\(\Rightarrow x.11,2=22,2\)

\(\Rightarrow x=\dfrac{111}{56}\)

Answer 4

\(\left(x+4\right)+\left(x+6\right)+...+\left(x+26\right)=210\\ \Rightarrow\left(x+x+...+x\right)+\left(4+6+...+26\right)=210\\ \Rightarrow12x+180=210\\ \Rightarrow12x=30\\ \Rightarrow x=\dfrac{5}{2}\)