7. Is the following a function? {(1,3), (2,4), (3,5),(4,10), (5,15),(3,5)}

Yes it's a function.

Explanation:

While x = 3 does repeat itself, the y value repeats itself as well for this particular x value. In other words, we have two copies of (3,5). Toss out any duplicate (x,y) pairings and we have this simplified set:

{(1,3), (2,4), (3,5), (4,10), (5,15)}

At this point, we don't have any repeated x values. Therefore, we have a function. Any input x leads to exactly one y output. The y values are allowed to repeat themselves.

Extra info:

No

Step-by-step explanation:

If you look at the numbers in each pair, three is the first number (x) in 2 of them. Functions cannot have repeating Xs.

y= (-9/2)*x-5/2  or  2y+9x+5=0

Step-by-step explanation:

given the following equation

y² = 5*x⁴ - x²

we can take the derivative with respect to x in both sides to get the slope of the tangent line , and knowing that y=f(x) we can apply the chain rule , therefore

d(y²)/dx = d(5*x⁴ - x²)/dx

2*y*dy/dx = 5*4*x³ - 2*x

dy/dx = (10*x³-x)/y

replacing values (x=-1,y=2)

m=dy/dx = (10*(-1)³-(-1))/2 = -9/2

now from the equation of the line

y= m*x+h

we know that (x=-1,y=2) belongs also to the line since it is tangent to the curve, thus

2= (-9/2)*(-1) + h

h = 2 - 9/2 = (-5/2)

thus

y= (-9/2)*x-5/2

or

2y+9x+5=0