Ok, I assume you know why the answer is not A, B or D. For why the answer is not C, see below:jimmiejaz wrote:Hi Stuart,
thanks for the explanation. But i still have a doubt.
From 2nd statement we have x= +y
yes, both x and y can be sqrt(70) too.
But, if we take x=-y don't we get -y^2 which cant be posiible as its a square.
I am confused in this.
x=sqrt70
y=-sqrt70
y^2 gives you +70 (a negative number squared is positive). x^2 also gives you +70. However x is positive, y is negative, so xy is negative. Always. xy can not be 70 because 70 is positive.
Those are the only two values that make BOTH statements 1 and 2 true.
