Answer:
x=-4 x=2
Step-by-step explanation:
y = x^2 + 2x - 8
Set equal to zero
0 = x^2 + 2x - 8
Factor
What two numbers multiply to -8 and add to 2
4 * -2 = -8
4+-2 = 2
0=(x+4) ( x-2)
Using the zero product property
x+4 =0 x-2 =0
x=-4 x=2
Exponential functions are in the form
, where <em>a</em> is the initial value, <em>b</em> is the growth rate (percent increase) + 1, and <em>x</em> is the number of time periods. Our initial value is 100, and we're given the growth rate + 1 (tripling is the same as increasing by 200%; 200%=2.0; 2.0+1=3). Therefore our function is
.
Answer:(4 x 0, 4 x ( - 1)), or 0, -4)
Y = height
x = distance from tower
tan(19.9) = y/x
tan(21.8) = y/(x-50) ( x is 50 feet closer so subtract 50 from x)
find the tan of the angles:
tan19.9 = 0.362
tan21.8 = 0.400
replace those values in the equations:
0.362 = y /x
0.400 = y / (x-50)
rewrite to solve for height:
0.362x = y
0.400(x-50) = y distribute the 0.400 and rewrite as 0.400x-20 =y
now solve:
0.362x = 0.400x-20
add 20 to each side:
0.362x +20 = 0.400x
subtract 0.362x from each side:
20 = 0.038x
divide both sides by 0.038
x = 20 / 0.038 = 526.3 feet
now that x is known replace x in the original equation and solve for y:
tan19.9 = y /x
0.362 = y / 526.3
y = 0.362 x 526.3
y = 190.5
the height of the tower is 190.5 feet
Answer:
see below
Step-by-step explanation:
x=0.5. by substitution we get 10(0.5)-4=5-4=1
