If (4x² − 3y²) : (2x² + 5y²) = 12 : 19, find x : y.

If x² + 4y² = 4xy, find x : y.

A ratio is equal to 3 : 4. If its consequent is 144, what is its antecedent?

Two numbers are in the ratio 8 : 13. If 14 is added to each of the numbers, the ratio becomes 2 : 3. Find the numbers.