Equations:
4x - 2y = 12
-4x - 9y = 54
Multiple them in both sides
4x - 2y - 4x - 9y = 12 + 54
-2y - 9y = 66
-11y = 66
y= -6
If y= -6 then put y in first or second equation.
I put it in first equation
4x - 2.(-6) = 12
4x + 12 = 12
x= 0
Therefore
(x,y) = (0, -6)
Answer:
y = -2x
Step-by-step explanation:
It passes through -5, 10 and 5, -10
gradient = Δy/Δx
gradient = -10 - 10 / 5 -- 5
gradient = -20 / 10
gradient = -2
let's use -5, 10 for y = mx + b
10 = -2(-5) + b
10 = 10 + b
b = 10 - 10
b = 0.
the equation of the line is just y = -2x
The ratio of the circumference to the diameter is defined as pi
pi=circumference/diameter
that is how they got pi
in this question it woul be 15.7/5 which would be 3.14,
c=2pir
a=pir^2
c=2pir=16pi
divide both sides by 2pi
r=8
a=pir^2
a=pi8^2
a=pi64
a=64pi in²