Answer: [tex]\dfrac{x^2}{81}+\dfrac{y^2}{32}=1[/tex]
Step-by-step explanation:
The standard form of equation of ellipse with foci (±c,0) as:
[tex]\dfrac{x^2}{a^2}+\dfrac{y^2}{b^2}=1[/tex]
, where major axis = 2a and minor axis = 2b
Given: Foci: (±7, 0); major axis of length 18
i.e. c= 7 and 2a =18 ⇒a= 9
Also,
[tex]c^2=a^2-b^2\Rightarrow\ b^2= a^2-c^2\\\\\Rightarrow\ b^2={9^2-7^2}={81-49}\\\\\Rightarrow\ b^2=32[/tex]
Put value of [tex]a^2[/tex] and [tex]b^2[/tex] , we get the required equation :
[tex]\dfrac{x^2}{81}+\dfrac{y^2}{32}=1[/tex]
