By "y = −9x2 − 2x" I assume you meant <span>y = −9x^2 − 2x (the "^" symbol represents exponentiation).
Let's find the first derivative of y with respect to x: dy/dx = -18x - 2. This is equivalent to the slope of the tangent line to the (parabolic) curve. Now let this derivative (slope) = 0 and solve for the critical value: -18x - 2 = 0, or
-18x = 2. Solving for x, x = -2/18, or x = -1/9.
When x = -1/9, y = -9(-1/9)^2 - 2(-1/9). This simplifies to y = -9/9 + 2/9, or
y = -7/9.
The only point at which the tangent to the curve is horiz. is (-1/9,-7/9).</span>
Answer:
The answer would be (1.23, 4.39)
Step-by-step explanation:
Because they are both equal to y, we can set the equations equal to each other and then solve.
4.9x - 1.64 = -0.25x + 4.7
5.15x - 1.64 = 4.7
5.15x = 6.34
x = 1.23
Now that we have the value for x, we can plug into either equation and find y.
y = -0.25x + 4.7
y = -0.25(1.23) + 4.7
y = -.31 + 4.7
y = 4.39
Answer:
Step-by-step explanation:
I'm still not exactly sure what the question really is, but the level suggests that it is
y = (6/7)x + 5
Any line that is parallel to this line has a slope of 6/7
Any line that is perpendicular to this line is a little more complicated.
slope of given line * slope of perpendicular line = - 1
6/7 * perpendicular slope = - 1
Multiply by 7
6*perpendicular slope = - 7
Divide by 6
perpendicular slope = - 7/6
Answer:area of the circle=πr²
3.14 =3.14 ×r²
r²= 1
r. =1 millimeters
She had 42 dollars.
(4/7 of 42 is 24 dollars)
