Question

POLYNOMIALS AND FACTORISATION

6. If a + b + c = 9 and ab + bc + ca = 26, find a^2+b^2+c^2
7. Evaluate the following using suitable identities 1)99^3 2)102^3 3)998^3 4)1001^3​

Answer 1

Step-by-step explanation:

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

a^2+b^2+c^2+2ab+2bc+2ca=81

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

a^2+b^2+c^2+2(26)=81

a^2+b^2+c^2+52=81

a^2+b^2+c^2=81-52

a^2+b^2+c^2=29

Answer 2

Answer:

6. (a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ca

(9)^2 =a^2+b^2+c^2+2(ab+bc+ca)

(9)^2=a^2+b^2+c^2+2*26

81=a^2+b^2+c^2+52

81-52=a^2+b^2+c^2

a^2+b^2+c^2=29