To find a percentage of a number, multiply by the decimal form of that percentage(20%=0.20). So, take the cost, $430, and multiply by common state sales tax (7% for me)---430 x 0.07 = 30.10 The sale tax rate is 7%.
Answer:
y = -2x^2(x - 3)
Step-by-step explanation:
<em><u>Preliminary Remark</u></em>
If a cubic is tangent to the x axis at 0,0
Then the equation must be related to y = a*x^2(x - h)
<em><u>(3,0)</u></em>
If the cubic goes through the point (3,0), then the equation will become
0 = a*3^2(3 - h)
0 = 9a (3 - h)
0 = 27a - 9ah
from which h = 3
<em><u>From the second point, we get</u></em>
4 = ax^2(x - 3)
4 = a(1)^2(1 - 3)
4 = a(-2)
a = 4 / - 2
a = -2
<em><u>Answer</u></em>
y = -2x^2(x - 3)
So y+x=2
x-y=4
one way is subsituteion where yousubisutte one of the number for another exg
x-y=4
add y to both sides
x=y+4
subsitute y+4 for x in x+y=2
y+4+y=2
2y+4=2
subtract 4 from both sides
2y=-2
divide both sides by 2
y=-1
subsiutte
x+y=2
x-1=2
x=3
or elimination
x+y=2
x-y=4
add the two equations and cancel the y terms
x+x+y-y=2+4
2x=6
divide both sides by 2
x==3
subsitute
x+y=2
3+y=2
y=-1
so x=3
y=-1
