LEARN · EXPLAIN · REVISE

Find the line through (t,1) and (t,5).

Read the idea, work independently, then explain what changed.

TOPIC 01

Equations of lines and circles: mixed review

A mixed assessment: identify the method, justify it and revise your reasoning.

Use one hint at a time. A correction explains what changed, not just the final answer.

01 / Foundation#Your turn

t=21

Point-slope form omits vertical lines; intercept form requires nonzero intercepts.

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1

Translate the geometric condition into a coordinate equation.

Hint 2

Use this intermediate relation.

x_1=x_2

Worked solution

Translate the geometric condition into a coordinate equation.
Apply the stated relation and retain its conditions.
$x=21$
Use a vertical equation directly instead of dividing by zero in a slope formula.

The requested relation or conclusion is shown below.

x=21

Checks and common pitfalls: Use a vertical equation directly instead of dividing by zero in a slope formula.

Reasoning checklist · self / teacher assessment

Think first. Reveal a hint when the class is ready.

Teacher preparation and assessment