What do you have to solve ?
Add five to both sides
-3x = 21
Divide by -3 on both sides
x = -7
Let's call the width
. Since the length is three more than the width, it is
.
The area (which we know to be 70) is given by the multiplication of width and length:
![x(x+3) = 70 \iff x^2+3x = 70 \iff x^2+3x-70 = 0](https://tex.z-dn.net/?f=%20x%28x%2B3%29%20%3D%2070%20%5Ciff%20x%5E2%2B3x%20%3D%2070%20%5Ciff%20x%5E2%2B3x-70%20%3D%200%20)
To solve this equation, you can use the usual quadratic formula: given an equation
, the two solutions are
![x_{1,2} = \frac{-b\pm\sqrt{b^2-4ac}}{2a}](https://tex.z-dn.net/?f=%20x_%7B1%2C2%7D%20%3D%20%5Cfrac%7B-b%5Cpm%5Csqrt%7Bb%5E2-4ac%7D%7D%7B2a%7D%20)
which in your case becomes
![x_{1,2} = \frac{-3\pm\sqrt{9+280}}{2} = \frac{-3\pm 17}{2}](https://tex.z-dn.net/?f=%20x_%7B1%2C2%7D%20%3D%20%5Cfrac%7B-3%5Cpm%5Csqrt%7B9%2B280%7D%7D%7B2%7D%20%20%3D%20%5Cfrac%7B-3%5Cpm%2017%7D%7B2%7D)
So, two solutions are
![\frac{-3-17}{20} = -10,\qquad \frac{-3+17}{2} = 7](https://tex.z-dn.net/?f=%20%5Cfrac%7B-3-17%7D%7B20%7D%20%3D%20-10%2C%5Cqquad%20%5Cfrac%7B-3%2B17%7D%7B2%7D%20%3D%207%20)
Since we can't accept a negative length, we only accept the second solution.
So, the dimensions are 7 and 10
8-6=2 2x9=18 so x should equal 18
Answer: parabola
Step-by-step explanation: