Question

If 4x +5y is equal to 23 and xy is equal to 6,find the value of 16x square + 25 y square

Answer 1

Answer:

289

Step-by-step explanation:

$(4x + 5y) {}^{2} = (23) {}^{2} \\ = > 16 {x}^{2} + 2 \times 4x \times 5y + 25 {y}^{2} = 529 \\ = > 16 {x}^{2} + 25 {y}^{2} + 40 \times 6 = 529 \\ = > 16 {x}^{2} + 25 {y}^{2} = 529 - 240 \\ = > 16 {x}^{2} + 25 {y}^{2} = 289$