The tangent line to <em>y</em> = <em>f(x)</em> at a point (<em>a</em>, <em>f(a)</em> ) has slope d<em>y</em>/d<em>x</em> at <em>x</em> = <em>a</em>. So first compute the derivative:
<em>y</em> = <em>x</em>² - 9<em>x</em> → d<em>y</em>/d<em>x</em> = 2<em>x</em> - 9
When <em>x</em> = 4, the function takes on a value of
<em>y</em> = 4² - 9•4 = -20
and the derivative is
d<em>y</em>/d<em>x</em> (4) = 2•4 - 9 = -1
Then use the point-slope formula to get the equation of the tangent line:
<em>y</em> - (-20) = -1 (<em>x</em> - 4)
<em>y</em> + 20 = -<em>x</em> + 4
<em>y</em> = -<em>x</em> - 24
The normal line is perpendicular to the tangent, so its slope is -1/(-1) = 1. It passes through the same point, so its equation is
<em>y</em> - (-20) = 1 (<em>x</em> - 4)
<em>y</em> + 20 = <em>x</em> - 4
<em>y</em> = <em>x</em> - 24
Answer:
Rewrite the equation as
3
b
+
4
c
=
a
.
3
b
+
4
c
=
a
Subtract
4
c
from both sides of the equation.
3
b
=
a
−
4
c
Divide each term by
3
and simplify.
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b
=
a
3
−
4
c
3
Step-by-step explanation:
f(x)=20+300x
Also, Rex should find a different pool because that fee is ridiculous.
Answer:I believe 786.34
Step-by-step explanation:
You divide 180 by 73.25 which is 2.46, then multiply this number by your 320 minutes to get the answer
