y varies directly with x.
The formula for direct variation is y= kx, k being the constant of variation. The constant of variation means: whenever you multiply x by this number, it will give you y.
1) Work out k.
When y is -26 x is 26, so -26= k x 26.
To work out k from this, divide -26 by 26, which will give you -1.
So k=-1.
That means, the formula for this will be y= -1x.
So whenever you multiply x by -1, it will give you y.
2) Find y when x=21.
y= -1 x 21
y= -21
The answer is -21
(SO SORRY IF I AM WRONG BTW)