Hi there!

First we need to work out the parenthesis, which can for instance be done using rainbow technique.

Now subtract 3 from both sides.

And finally add 3x to both sides.

The 4th answer choice is correct.
Answer:
The solutions of the equation x^2-1=-x^2+7 are (-2,3) and (2,3)
Step-by-step explanation:
Please, see the attached file.
Thanks.
Answer:
348 frogs
Step-by-step explanation:
ratio = 3:7
total of ratio = 10
frogs = 3/10 × 1280 = 348 frogs