(1,3) means that x = 1 and y = 3. Let's make substitutions to see what happens with the inequality
5*x + y < -3
5*1 + y < -3 ... replace x with 1
5*1 + 3 < -3 ... replace y with 3
5 + 3 < -3
8 < -3
This is false. The number 8 is NOT smaller than -3.
So (1,3) is NOT a solution
Answer: Choice A) No
A ball is at it maximum height when its velocity is zero. y = 4+30t - 16t^2 is the formula, where
V = V(0) -32t
0 = 30- 32t
t = 15/16 seconds when its velocity is zero.
It is not at its maximum height but is falling.
Givens
y = 2
x = 1
z(the hypotenuse) = √(2^2 + 1^2) = √5
Cos(u) = x value / hypotenuse = 1/√5
Sin(u) = y value / hypotenuse = 2/√5
Solve for sin2u
Sin(2u) = 2*sin(u)*cos(u)
Sin(2u) = 2(
) = 4/5
Solve for cos(2u)
cos(2u) = - sqrt(1 - sin^2(2u))
Cos(2u) = - sqrt(1 - (4/5)^2 )
Cos(2u) = -sqrt(1 - 16/25)
cos(2u) = -sqrt(9/25)
cos(2u) = -3/5
Solve for Tan(2u)
tan(2u) = sin(2u) / cos(2u) = 4/5// - 3/5 = - 0.8/0.6 = - 1.3333 = - 4/3
Notes
One: Notice that you would normally rationalize the denominator, but you don't have to in this case. The formulas are such that they perform the rationalizations themselves.
Two: Notice the sign on the cos(2u). The sin is plus even though the angle (2u) is in the second quadrant. The cos is different. It is about 126 degrees which would make it a negative root (9/25)
Three: If you are uncomfortable with the tan, you could do fractions.

A+2b=3000
90a+60b=150000
-90a-180b=-127000
90a+60b=150000
-120b=-120000
b=1000
a+2000=3000
a=1000
crop a=1000
crop b=1000
Slope formula (y2-y1)/(x2-x1)
(x1,y1) (x2,y2)