Answer:
$2.64
Step-by-step explanation:
9 coins are pennies (reply to my comment if you want to know how I got it)
19 coins are dimes (reply to my comment if you want to know how I got it)
9 (pennies) + 4 = 13 (nickels)
$1.90 (dimes) + $0.09 (pennies) + $0.65 (nickels) = $2.64
18-4x=7x+7
11-4x=7x
11=11x
x=1
<span>Distance = d miles ; rate = 60 mph ; time = d/60 hrs
distance = d miles ; rate = 50 mph ; time = d/50 hrs
----------------------
Round-trip DATA:
distance = 2d miles ; rate = 55 mph ; time = (2d)/55 hrs
-----------------------------------------------------------
Equation:
Roundtrip time - other time = -1/2 hr
(2d)/55 - [(d/60)+(d/50)] = -1/2
(2d)/55 - [(110d)/(50*60)] = -1/2
---
600(2d) - 11[110d] = -16500
1200d - 1210d = -16500
-10d = -16500
distance = 1650 miles
Hope this helped :)</span>
This is the answer: X= 118
(3) Differentiating both sides of

with respect to <em>x</em> gives

Solve for d<em>y</em>/d<em>x</em> :

Then the slope of the tangent line to the curve at (1, 9) is

The equation of the tangent line would then be
<em>y</em> - 9 = -2/3 (<em>x</em> - 1) ==> <em>y</em> = -2/3 <em>x</em> + 29/3
(4) The slope of the tangent line to

at a point <em>(x, y)</em> on the curve is

When <em>x</em> = -1, we have a slope of 2/3, so
-(2<em>a</em> + 1)/(-1 - 2)² = 2/3
Solve for <em>a</em> :
-(2<em>a</em> + 1)/9 = 2/3
2<em>a</em> + 1 = -18/3 = -6
2<em>a</em> = -7
<em>a</em> = -7/2