Question

if x and y are two positive real numbers such that 25 x square + 49 y square equals to 841 and xy equals to 12 then find the value of 125 x cube + 343 y cube​

Answer 1

Answer:

Step-by-step explanation:

25x²+49y²=841

xy=12

y=12/x

25x²+49(12/x)²=841

25x²+7256/x²=841

25x4+7256=841x²

25x4-841x²+7256=0

x=4,-4,21/5,-21/5

since x is positive number

x=4,21/5

since y=12/x

y=3,20/7

so,

125x^+343y^3 =17261