Check the picture below.
![\bf A=\cfrac{h(a+b)}{2}\quad \begin{cases} A=20\\ a=6z-1\\ b=2z+3\\ h=z \end{cases}\implies 20=\cfrac{z[(6z-1)~+~(2z+3)]}{2} \\\\\\ 20=\cfrac{z(8z+2)}{2}\implies 20=\cfrac{2z(4z+1)}{2}\implies 20=z(4z+1) \\\\\\ 20=4z^2+z\implies 0=4z^2+z-20](https://tex.z-dn.net/?f=%5Cbf%20A%3D%5Ccfrac%7Bh%28a%2Bb%29%7D%7B2%7D%5Cquad%20%0A%5Cbegin%7Bcases%7D%0AA%3D20%5C%5C%0Aa%3D6z-1%5C%5C%0Ab%3D2z%2B3%5C%5C%0Ah%3Dz%0A%5Cend%7Bcases%7D%5Cimplies%2020%3D%5Ccfrac%7Bz%5B%286z-1%29~%2B~%282z%2B3%29%5D%7D%7B2%7D%0A%5C%5C%5C%5C%5C%5C%0A20%3D%5Ccfrac%7Bz%288z%2B2%29%7D%7B2%7D%5Cimplies%2020%3D%5Ccfrac%7B2z%284z%2B1%29%7D%7B2%7D%5Cimplies%2020%3Dz%284z%2B1%29%0A%5C%5C%5C%5C%5C%5C%0A20%3D4z%5E2%2Bz%5Cimplies%200%3D4z%5E2%2Bz-20)

since the height is just a length unit, it can't be -2.3646.
Answer:
=2.4 cm
Step-by-step explanation:
In similar plane figures, the ratio of corresponding sides is a constant.
This constant is the linear scale factor.
In the provided example, 1.2cm corresponds to 0.96 while 3.0 corresponds to x
Thus, 1.2 cm/0.96 cm=3.0 cm/x
x=(3.0 cm×0.96 cm)/1.2 cm
=2.4 cm.
Answer: -2
Step-by-step explanation:
<h2>
Answer:</h2><h2>
The population of the city after 7 years = 569,859</h2>
Step-by-step explanation:
The population of the city of Miami = 463,300
The rate of increase in population every year = 3%
The population of the city after 7 years = ?
By formula, 
Pn is the population after 7 years
P is the current population = 463,300
r = 3 %, n = 7

= 463300 (1.23)
= 569859
The population of the city after 7 years = 569,859