Question

if a+b=17 and ab is 72 , then find a-b​

Answer 1

Step-by-step explanation:

we have the formula:

(a + b) ² = a² + b² + 2ab

17² = a² + b² + 2*72

a² + b² = 289 - 144

a² + b² = 145

Now,

(a - b)² = a² + b² - 2ab

(a - b)² = 145 - 2*72

(a - b)² = 1

(a - b) = 1

Answer 2

Answer:

1

Step-by-step explanation:

a+b = 17 - (i)

ab = 72 - (ii)

Formula - ( a + b ) ² = a² + b² + 2ab

Take square of first equation

= 17² = 289

289 = a² + b² + 2 × 72

289 = a² + b² + 144

a² + b² = 289 - 144

a² + b² = 145

Now formula of (a-b)² = a² + b² - 2ab

Now put value of a² + b² and ab in above equation

(a-b)² = 145 - 2×72

(a-b)² = 145 - 144

(a-b)² = 1

square root both sides

a-b = √1

a-b = 1