insert grouping symbols into 2x3^3+4 to get it to equal 4374 and 279,936.

Answer 1

Since ^ (exponentiation) has the highest priority of the three, parentheses could be put around 2×3 or 3+4 to get:
(2×3)^(3+4), or
2&times 3^(3+4), or
(2×3)^3 + 4

Two of the above will give the required answers.