Question

Tìm a:

a + 90 = 190 - 20

a x 10 = 900

Answer 1

\(a+90=190-20\)

\(\Leftrightarrow a+90=170\)

\(\Leftrightarrow a=170-90\)

\(\Leftrightarrow a=80\)

\(a\times10=900\)

\(\Leftrightarrow a=900\div10\)

\(\Leftrightarrow a=90\)

Answer 2

a + 90 = 190 - 20

<=> a + 90 = 170

a = 170 - 90

a = 80

_______________

a x 10 = 900

a = 900 : 10

a = 90

Answer 3

\(a+90=170\)

\(a=170-90\)

\(a=80\)

\(a=900:10=90\)

Answer 4

a + 90 = 190 - 20

a + 90 = 170

a         = 170 - 90

a         = 80

a x 10 = 900

a        = 900 : 10

a        = 90