Since the foci (±3, 0) lie on x-axis. ∴ The equation of ellipse in standard form is $\frac{x^2}{a^2}+\frac{y^2}{b^2}$ = 1 Now, foci are (±3, 0) ⇒ c = 3 We know that $c^2$ = $a^2 - b^2$ ∴ $(3)^2$ = $(4)^2 - b^2$ ⇒ $b^2$ = 16 – 9 = 7. Hence the required equation of ellipse is $\frac{x^2}{16}+\frac{y^2}{7}$ = 1.