Answer:
120 square feet
Step-by-step explanation:
Area = length x width
Insert the two values. Width will represent height.
Area = 12 x 10
Solve.
For # 3 and 5 you need to use the quadratic formula:
<span>(-b +/- srt(b^2 - 4ac))/2a </span>
<span>a, b, and c are representative of this formula: ax^2 +bx + c </span>
<span>1) 2x^2+3x-9=0 </span>
<span>(2x - 3)(x + 3) = 0 </span>
<span>2x - 3 = 0, x + 3 = 0 </span>
<span>+3 +3, -3 -3 </span>
<span>2x = 3, ***x = -3*** </span>
<span>/2 /2 </span>
<span>***x = 3/2*** </span>
<span>2) 5x^2+2x=0 </span>
<span>(x)(5x + 2) = 0 </span>
<span>5x +2 = 0, ***x = 0*** </span>
<span>-2 -2 </span>
<span>5x = -2 </span>
<span>/5 /5 </span>
<span>***x = -2/5*** </span>
<span>4) 4x^2+7x-2=0 </span>
<span>(4x - 1)(x + 2) = 0 </span>
<span>4x - 1 = 0, x + 2 = 0 </span>
<span>+1 +1, -2 -2 </span>
<span>4x = 1, ***x = -2*** </span>
<span>/4 /4 </span>
<span>***x = 1/4***</span>
Use the equation for the volume of a cone to solve for the height:
<u>Answer:</u>
29 years
<u>Step-by-step explanation:</u>
- Given the function
, where x stands for the number of years since the material was put into the vault, we can plug 140 into x to find the amount leftover. - Another way of doing this is to change the function to
which are equivalent functions, and then plug 140 into x. This function is helpful if you also needed to find the rate. - I'll use the 1st function because the question doesn't ask for the rate
From here I'll just use a calculator & get 28.7, or 29 years.
