Question 286·Easy·Algebra

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If $0.5t - 1.5 = 0$ , what is the value of $t - 3$ ?

In a linear equation, the unknown is only to the first power. A Desmos regression can find its value by replacing $=$ with $\sim$ . Finding the unknown and evaluating the requested expression are two separate jobs. The zero on one side of an equation isn't automatically the value of the unknown.

Hints

Hint 1
A solution is a value of $t$ that makes both sides equal. Replace the equals sign with $\sim$ in Desmos to find that value. Which letter does Desmos report under PARAMETERS?
Hint 2
The equation helps you find $t$ , but the question asks for an expression involving $t$ . Once you know $t$ , put its value into $t-3$ .

Step-by-step

Approach 1: Solve in Desmos, then evaluate
Step 1
Find the value of $t$
Type $0.5t-1.5\sim0$ . The regression symbol $\sim$ tells Desmos to find a value of $t$ that makes both sides equal. Under PARAMETERS, Desmos shows $t=3$ , so that value satisfies the given equation.
Step 2
Evaluate what the question asks for
Type the requested expression, $t-3$ , on the next line. Desmos uses $t=3$ and displays $0$ . So the value of $t-3$ is $0$ . Choice B.

Approach 2: Spot the requested expression inside the equation
Step 1
Factor out $0.5$
Because $1.5=0.5(3)$ , factor $0.5$ out of the left side to reveal the expression asked for:
$0.5(t-3)=0.$
Step 2
Divide by the nonzero factor
Divide both sides by $0.5$ , which is not zero: $t-3=0$ . The equation gives the requested value directly: $0$ . Choice B.

Question 286·Easy·Algebra

Strategy

Hints

Step-by-step

Lessons that teach this

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Strategy

Hints

Step-by-step

Lessons that teach this