CAIE IGCSE Mathematics Extended E2.10.2 Solve Equations Graphically Questions

Review CAIE IGCSE Mathematics solving equations graphically through roots, intersections, suitable straight lines and reading values from curves.

Exam points

Solve equations graphically by drawing suitable lines, reading roots and intersections accurately, and selecting positions that produce the required solutions.

[Maximum number: 6]

The straight line y=2 x+1 intersects the curve $y=x^{2}+3 \boldsymbol{x}-4$ at the points A and B.

Find the coordinates of A and B.
Give your answers correct to 2 decimal places.

(-2.79,-4.58) and (1.79,4.58)

B5 for $(-2.791,-4.583\text{ to }-4.582)$ and $(1.791,4.582\text{ to }4.583)$ , or B4 for -2.79 or -2.791 and 1.79 or 1.791.
OR
M1 for $2x+1=x^2+3x-4$ or better.
M2 for $\frac{-1\pm\sqrt{1^2-4(1)(-5)}}{2(1)}$ .
FT their quadratic not $x^2+3x-4$ ;
or M1 for $\frac{-1\pm p}{2(1)}$ or $1^2-4(1)(-5)$ , FT their quadratic not $x^2+3x-4$ .

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CAIE IGCSE Mathematics Extended E2.10.2 Solve Equations Graphically Questions question 1