Question

12. if x + 5y = 9 and xy = 4, find the value of (x2 + 25y).​

Answer 1

Answer:

41

Step-by-step explanation:

=> x+5y = 9

Squaring both sides we get:

=> (x+5y)² = (9)²

=> (x)²+(5y)²+2(x)(5y) = 81

=> x²+25y²+10xy = 81

Putting xy = 4 from (i)

=> x²+25y²+10(4) = 81

=> x²+25y² +40 = 81

=> x²+25y² = 81-40

=> x²+25y² = 41

Value of x²+25y² = 41.

Answer 2

Answer:

41

Step-by-step explanation:

x^2+(5y)^2 +2×x×5y = (x+5y)^2

x^2+ (5y)^2 +2×5×xy = (9)^2

x^2 +(5y)^2 + 10×4 = 81

x^2+( 5y)^2 + 40 = 81

x^2+25y^2 = 81-40= 41