The line through the right focus and P=(2,1) also passes through A=(0,−1). Find its equation.

01 / Standard#Your turn

Official paper · jm02-2025 · 3(a) · PDF 5

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1

Two known points already determine the line.

Hint 2

Use the y-intercept at A.

Worked solution

y=x−1.

Checks and common pitfalls: The focus coordinates are not needed for this first step.

Reasoning checklist · self / teacher assessment

Teaching assessment checklist, independently authored. Use the original paper for official marks.
Calculate the slope from A and P.
$m=\frac{1-(-1)}{2-0}=1$
Insert A in the point-slope equation.
$y+1=x\implies y=x-1$

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

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