15, Yes: a^2 +b^2 = c^2
9^2+12^2= 225
The square root of 225 is 15, therefore x=15.
Answer to question is yes.
This is a simple formula:(a-b)*(a+b)= a^2-b^2
And it goes like this for your example: (a-1)*(a+1)=a*a+a-a-1*1=a^2-1^2=a^2-1
3(x - 25) < $100. We're not req'd to solve this.
Area covered by the solar cells = 269.5 m^2
Area of one cell = 150 cm^2
Convert the area of one cell to m^2 by using the conversion factor 1m^2 = (100cm)^2 => 1 = 1m^2 / 1000 cm^2
=> 150 cm^2 * [1m^2 / 1000 cm^2] = 0.150 m^2
Now finf the number of times that 0.150 is contained in 269.5 by dividing 269.5 by 0.150
269.5 = 0.150 = 1,796.67
Which means that the number of cells is betwee 1796 and 1797.