Answer:
6. r=2
8.x=3
Step-by-step explanation:
6. 4r-3=5
4r-3=5 add 3 to both sides
4r=8 divide 4 by both sides
r=2
8. 5x-6=9
5x-6=9 add 6 to both sides
5x=15 divide 5 by both sides
x=3
Answer:
7 and 1/4 or 7.25
Step-by-step explanation:
28/4 = 7
1/4 = 0.25
7 + 0.25 = 7.25

To find the gradient of the tangent, we must first differentiate the function.

The gradient at x = 0 is given by evaluating f'(0).

The derivative of the function at this point is negative, which tells us <em>the function is decreasing at that point</em>.
The tangent to the line is a straight line, so we will have a linear equation of the form y = mx + c. We know the gradient, m, is equal to -1, so

Now we need to substitute a point on the tangent into this equation to find c. We know a point when x = 0 lies on here. To find the y-coordinate of this point we need to evaluate f(0).

So the point (0, -1) lies on the tangent. Substituting into the tangent equation:
Answer:
y³ + x³ = 1
First, differentiate the first time, term by term:

↑ we'll substitute this later (4th step onwards)
Differentiate the second time:

