The answer is :
2x^2 + 7x - 4
Given:
The value of the solid's surface area is equal to the value of the solid's volume.
Length(l) = 9 units
width(b) = 4 units
Height(h) = x units
To find:
The value of x.
Solution:
Solid's surface area is





Volume of solid is



Solid's surface area = Volume of solid



Divide both sides by 10.

Therefore, the value of x is 7.2.
"<span>z˄2 − 3" because x squared is z^2, and 3 less of it would mean to subtract it from 3</span>
There would be 12 people at the party!
In general, with n+1 people, the number of handshakes is the sum of the first n consecutive numbers: 1+2+3+ ... + n.
Since this sum is n(n+1)/2, we need to solve the equation n(n+1)/2 = 66.
This is the quadratic equation n2+ n -132 = 0. Solving for n, we obtain 11 as the answer and deduce that there were 12 people at the party.
Since 66 is a relatively small number, you can also solve this problem with a hand calculator. Add 1 + 2 = + 3 = +... etc. until the total is 66. The last number that you entered (11) is n.
Hope this helps!