Complete the working below to make $x$ the subject of $2x+7=y$
$\begin{aligned}
2 x+7 & =y \
2 x & =y-7
\end{aligned}$
Answer (2)
To make x the subject of the equation 2 x + 7 = y , subtract 7 from both sides to get 2 x = y − 7 . Then, divide by 2 to isolate x , resulting in x = 2 y − 7 . Therefore, the final answer is x = 2 y − 7 .
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Start with the equation 2 x + 7 = y .
Subtract 7 from both sides: 2 x = y − 7 .
Divide both sides by 2 to isolate x : x = 2 y − 7 .
The final answer is x = 2 y − 7 .
Explanation
Isolating x We are given the equation 2 x + 7 = y and we want to make x the subject. Amber has already started by subtracting 7 from both sides, resulting in 2 x = y − 7 . Now we need to isolate x completely.
Dividing by 2 To isolate x , we need to divide both sides of the equation 2 x = y − 7 by 2. This gives us:
Final Result 2 2 x = 2 y − 7 x = 2 y − 7
Conclusion So, the final equation with x as the subject is x = 2 y − 7 .
Examples
In physics, you might use this type of equation to convert between different temperature scales. For example, if y represents the temperature in degrees Fahrenheit and x represents the temperature in degrees Celsius, the equation x = 1.8 y − 32 allows you to convert Fahrenheit to Celsius. Making a variable the subject of a formula is a fundamental skill in many scientific and engineering applications.
