Verify that `-(-x)=x`, when : `x=7/19`

Verify -(-x)=x for x= (-7)/(9)

Verify -(-x)=x for x=(3)/(5)

Verify -(-x)=x for x=(13)/(-15)

Verify that:- 18x [7+ (-3)] = [18x7] + [18x (-3)]

Verify that -2,1,5 are the zeroes of the cubic polynomial p(x)=x^(3)-4x^(2)-7x+10, and then verify the relationship between the zeroes and the coefficients.

Verify that x sgn x=|x|;|x|sgn x=xx(sgn x)(sgn x)=x

If x+y=19 and x-y=7, then xy= ?

Find x when 7:x::x:28

Verify Rolle's theorem for f(x)=x,x in[1,2] .

Verify by substitution that: x=4 is the root of 3x-5=7x=3 is the root of 5+3x=14