Question

What is T In the equation 3/7+t=20/21

Answer 1

`\large\boxed{t=(11)/(21)}`

Explanation:

`(3)/(7)+t=(20)/(21)\qquad\text{subtract}\ (3)/(7)\ \text{from both sides}\\\\(3)/(7)-(3)/(7)+t=(20)/(21)-(3)/(7)\qquad\text{LCD(7, 21)=21}\\\\t=(20)/(21)-(3\cdot3)/(7\cdot3)\\\\t=(20)/(21)-(9)/(21)\\\\t=(20-9)/(21)\\\\t=(11)/(21)`