Question

3) i) Find the value of ab + bc + ca, if a + b + c = 27 and a2 + b2 +2 = 105​

Answer 1

Answer:

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Step-by-step explanation:

Here mentioned three Equcation

Equcation No First is ab+bc+ca= ?

Equcation No Second is a+b+c=9

Equcation No Third is a^2+b^2+c^2=35

Now we squaring both side Equcation No Second then becomes results is

(a+b+c)^2=9^2

Then become a^2+b^2+c^2+2(ab+bc+ca)=81

Then you can get value from Equcation No Third and put at above Equcation then you find results is

35+2(ab+bc+ca)=81

Then ab+bc+ca=( 81–35)/2

Then ab+bc+ca= 46/2

Then final result is ab+bc+ca=23