a)x*5,2:4,5=10,4
x*5,2=10,4*4,5
x*5,2=46,8
x =46,8:5,2
x =9
b)5/7*x+2/7*x=2/3
x*(5/7+2/7)=2/3
x*1 =2/3
x =2/3:1
x =2/3
a.
\(x\times5,2\div4,5=10,4\)
\(x\times5,2=10,4\times4,5\)
\(x\times5,2=46,8\)
\(x=46,8\div5,2\)
\(x=9\)
b.
\(\dfrac{5}{7}\times x+\dfrac{2}{7}\times x=\dfrac{2}{3}\)
\(x\times\left(\dfrac{5}{7}+\dfrac{2}{7}\right)=\dfrac{2}{3}\)
\(x\times1=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}\div1\)
\(x=\dfrac{2}{3}\)