Question

4.2 + 7/20 = 420/100 + /100 Enter the number that makes the equation true

Answer 1

write the missing number as the letter x:

`4.2+(7)/(20)=(420)/(100)+(x)/(100)`

To solve x:

1. Siplify fraction 420/100 write it in decimals:

`4.2+(7)/(20)=4.2+(x)/(100)`

2. As 4.2 is possitive in both sides of the equation you substract 4.2 in both sides of the equation:

`\begin{gathered} \text{4}.2-4.2+(7)/(20)=4.2-4.2+(x)/(100) \\ \\ (7)/(20)=(x)/(100) \end{gathered}`

3. Multiply both sides of the equation by 100:

`\begin{gathered} 100\cdot(7)/(20)=100\cdot(x)/(100) \\ \\ (700)/(20)=x \end{gathered}`

4. Simplify:

`x=35`Then, the number in the blank space is 35