Question 331·Easy·Algebra

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What value of $k$ satisfies the equation $2k - 5 = 27$ ?

A linear equation with one unknown asks for the number that makes both sides equal. If a number is multiplied and then something is subtracted, undo the subtraction first, followed by the multiplication. You can check the original equation with a Desmos regression. Don’t mistake the value of twice the unknown for the unknown itself.

Hints

Hint 1
The $-5$ is applied to $2k$ , so undo that subtraction first. Add $5$ to both sides of the equation; changing both sides the same way keeps them equal.
Hint 2
The expression $2k$ means twice $k$ . Once you know its value, how do you find $k$ ? You can check by typing the original equation with $\sim$ in place of $=$ in Desmos.

Step-by-step

Undo the subtraction, then solve
Step 1
Find the value of twice $k$
The equation subtracts $5$ from $2k$ . Undo the last operation first. An equation stays true when you make the same change to both sides. Add $5$ to both sides:
$2k=32.$
Step 2
Find $k$
$2k$ means twice $k$ , so $32$ is not yet the value asked for. To find $k$ and check the original equation, type $2k-5\sim27$ in Desmos. The $\sim$ tells Desmos to solve for $k$ ; under PARAMETERS, it shows $k=16$ . So the value of $k$ is $16$ . Choice B.

Question 331·Easy·Algebra

Strategy

Hints

Step-by-step

Lessons that teach this

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Strategy

Hints

Step-by-step

Lessons that teach this