x is 2
we know that the volume of a rectangular prism is equal to
[tex]s.h = lwh[/tex]
which L stands for length, w for width and h for height. (the volume is equal to the product of length, width and height)
now you can make an equation for this :
[tex]2 \times \frac{7}{4} \times 10x = 7 0 \\35x = 70 \\ x = \frac{70}{35} = 2[/tex]
the value of x is 2
good luck