Introduction & Basics — JEE Main Mathematics MCQs with Solutions
Free JEE Main Mathematics Introduction & Basics MCQs with step-by-step solutions (2 questions). Part of Straight Lines. Practise online on Prepizo — no login needed.
▶ Practise Introduction & Basics online (free)
Questions with solutions
Q1 — Introduction & Basics · medium · numerical
The area (in square units) of the triangle with vertices $(2, 7)$, $(5, 1)$ and $(-1, 3)$ is:
A. $30$
B. $13$
C. $15$ ✓ Correct
D. $10$
Solution: Area $= \dfrac{1}{2}|2(1-3) + 5(3-7) + (-1)(7-1)| = \dfrac{1}{2}|-4 - 20 - 6| = 15$.
Q2 — Introduction & Basics · medium · numerical
If the points $(k, -2)$, $(3, 0)$ and $(7, 8)$ are collinear, then $k$ equals:
A. $-2$
B. $1$
C. $4$
D. $2$ ✓ Correct
Solution: Collinearity needs area $0$: $k(0-8) + 3(8+2) + 7(-2-0) = -8k + 16 = 0 \Rightarrow k = 2$.