Question

If a+b=30 and a^2+b^2=740 find the value of ab​

Answer 1

Explanation:

HERE,

a+b=30

a^2+b^2=740

we know that,

`\tt{(a+b)^2=a^2+b^2+2ab }`

according to the question,

`\tt{ (30)^2=740+2ab }`

`\tt{900=740+2ab }`

`\tt{ 2ab=900-740 }`

`\tt{ ab=(160)/(2) }`

`\tt{ab=80 }`

#quality answer

Answer 2

the value of ab is 80

Answer:

Solution given:

(a+b)=30....(1)

a²+b²=740......(2)

squaring equation 1:

we have;

formula:

(a+b)²=a²+b²+2ab

use this formula:

(a+b)²=30²

a²+b²+2ab=30²

Substituting value of a²+b²=740

740+2ab=30²

take constant term on one side.

2ab=30²-740

subtract :30²-740

2ab=160

divide both side by 2

2ab/2=160/2

we get:

ab=80

the value of ab is 80