2. Vanessa wants to model how a car's maintenance costs change as the distance someone drives the car increases. What would be a
1 answer:
You might be interested in
Answer:
- x = -1/2(1 +√21) ≈ -2.79129
- x = -1/2(1 -√21) ≈ 1.79129
Step-by-step explanation:
We assume the middle term is supposed to be 4x.
We can remove a common factor of 4 to simplify this a bit.
x^2 +x -5 = 0
This is of the form
ax^2 +bx +c = 0
where a=1, b=1, c=-5.
__
The <em>quadratic formula</em> gives the solutions as ...
Filling in the given coefficients, we have ...
x = (-1 ±√(1^2 -4·1·(-5)))/(2·1)
x = (-1±√21)/2
The solutions are x = -1/2(1 +√21) and -1/2(1 -√21).
_____
<em>If what you wrote is what you intend</em>, then the equation simplifies to 4x^2 -16 = 0.
Dividing by 4 and factoring the difference of squares gives ...
x^2 -4 = 0
(x -2)(x +2) = 0
These factors are zero (hence their product is 0) for the values x = 2 and x = -2.
The solutions are x=2 and x=-2.
Answer:
254 cm² (to 3 s.f.)
Step-by-step explanation:
Area of shaded region
= area of large circle -area of smaller circle
Radius of large circle= 15cm
Radius of smaller circle= 12cm
Area of shaded region
= π(15²) -π(12²)
= 225π -144π
= 81π
= 81(3.14)
= 254.34
= 254 cm² (3 s.f.)