Answer:
C
Step-by-step explanation:
We can solve simultaneous equations using substitution method, elimination method or graphical method. But for this purpose, we will be using the elimination method.
3x+4y=8 Equation 1
2x+y=42 Equation 2
Multiply Equation 1 by 2 and equation 2 by 3, so as to get the same coefficient for x
2(3x+4y=8)= 6x+8y=16 Equation 3
3(2x+y=42)= 6x+3y=126 Equation 4
Subtract equation 4 from 3, to eliminate x
6x-6x=0
8y-3y= 5y
16-126= -110
We now have 5y=-110
Divide both sides by 5,
y= -110/5
= -22
Substituting for y in equation 2
2x+(-22)= 42
2x= 42+22
2x=64
x= 64/2
= 32
(x, y)
(32, -22)
Circumference of a circle - derivation
This page describes how to derive the formula for the circumference of a circle.
Recall that the definition of pi (π) is the circumference c of any circle divided by its diameter d. Put as an equation, pi is defined as
π
=
c
d
Rearranging this to solve for c we get
c
=
π
d
The diameter of a circle is twice its radius, so substituting 2r for d
c
=
2
π
r
If you know the area
Recall that the area of a circle is given by
area
=
π
r
2
Solving this for r
r
2
=
a
π
So
r
=
√
a
π
The circumference c of a circle is
c
=
2
π
r
Answer:45 nickels
Step-by-step explanation:
If a nickel is $ 0.05 , than $ 2.25 divided by. $0.05 is 45.
Answer:
D
Step-by-step explanation:
An estimate for the percent equivalent of 7/15 is 46% i think
