To find the value of x, we can set up the equation:

40% of x = -7/2

To convert 40% to a decimal, we divide by 100:

0.40x = -7/2

To solve for x, we can multiply both sides of the equation by 2 to eliminate the fraction:

0.40x * 2 = (-7/2) * 2

0.80x = -7

Finally, we divide both sides of the equation by 0.80 to solve for x:

x = -7 / 0.80

x = -8.75