Question

Plz answer first three question i will mark brainliest

Answer 1

2) (a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca 
can solve the problem by this method

Answer 2

1. rationalising factor of √18

we can write √18 = √(9×2) = 3√2
on multipling it by √2 we get a rational no. i.e. 6
hence the rationalising factor is √2

2. using (x+y+z)^2 = x^2 + y^2 + z^2 + 2(xy+yz+zx)

(a+2b+3c)^2 = a^2 + 4b^2 + 9c^2 + 2(2ab+6bc+3ac)

3. reflection of point (-2,5) across the origin is (2,-5)..