Express y = -2x² - 4x + 7 in the form of perfect square and find the maximum points.
1 answer:
Answer:
<em>Maximum: (-1,9)</em>
Step-by-step explanation:
<u>Vertex form of the quadratic function</u>
If the graph of the quadratic function has a vertex at the point (h,k), then the function can be written as:
Where a is the leading coefficient.
We are given the following function:
To find the vertex, we need to complete squares. First, factor -2 on the first two terms:
The expression in parentheses must be completed to represent the square of a binomial. Adding 1 and subtracting 1:
Taking out the -1:
Factoring the trinomial and operating:
Comparing with the vertex form we have
Vertex (-1,9)
Leading coefficient: -2
Since the leading coefficient is negative, the function has a maximum value at its vertex, i.e.
Maximum: (-1,9)
You might be interested in
Answer:
Step-by-step explanation:
The length of a chalkboard, l = 1.7
The width of a chalkboard, b = 0.9 m
We need to find the area of the chalkboard. The formula for the area of a rectangle is given by :
So, the area of the chalkboard is equal to .
Answer:
a = $80.3
b = $80
c = 4
d = 16
e = 4
f = 88
g = $132
h = 33%
i = 6
j = 30
k = 21
l = $90
m = $36
o = 21/50
p = 105
q = 7
r = 8 cm
s = 2.4
t = 4
u = 400cm
v = $280
Step-by-step Explanation:
==>Increasing $72 by 10% to get a
a = 110% of $72 = 110% × $73
a = 1.1 × 73
a = $80.3
==>a ($80.3) rounded to the nearest 10 to find b = $80
b = $80
==>Writing b (80) as the product of its primes I.e.
Thus, 80 = 2⁴ * 5
c = 4
==>Calculating c² = d
d = 4² = 16
d = 16
==> ²/8 of d = e
e = ²/8 × 16
e = 2 × 2
e = 4
==> e% of 2200 = f
f = 4% × 2200
f = 0.04 × 2200
f = 88
==>Converting £f to $ = g
If £1 = $1.5,
£88 = $g
1 × g = 1.5 × 88
g = $132
==> Converting into % = h%
h = 132÷400 ×100
h = 0.33 × 100
h = 33%
==> √(h + 3) = i
i = √(33 + 3)
i = √36
i = 6
==> i × (3 + 2) = j
j = 6 × (3 + 2)
j = 6 × 5
j = 30
==> j% of 70 = k
k = j% × 70
k = 30% × 70
k = 0.3 × 70
k = 21
==> If k bottles = $63, 30 bottles = $l
21 bottles = $63
30 bottles = $l
21 × l = 63 × 30
21l = 1,890
l = 1,890/21
l = $90
==>If Tim and Mike (m) shares $90 in the ratio 3:2, Mike (m) would receive thus:
⅖ × $90 = m
m = 0.4 × 90
m = $36
==> √m + m = n
n = √36 + 36
n = 6 + 36
n = 42
==>Converting n% to fraction = o
Thus, o = 42/100
o = 21/50
==> o of 250 = p
p = 21/50 × 250
p = (21 × 250)/50
p = 21 × 5
p = 105
==> expressing p as a product of its primes i.e. p = 3 × 5 × q
105 = 3 × 5 × 7
Therefore, q = 7
==> Given a rectangle with dimensions of q cm and r cm, with an area of 56cm². Let's find r.
Area of rectangle = length × width = q × r
Area = 56 cm²
q = 7 cm
r = ?
56 = 7 × r
56/7 = r
8 = r
r = 8 cm
==> r × 0.3 = s
s = 8 × 0.3
s = 2.4
==> s ÷ 0.6 = t
t = 2.4 ÷ 0.6
t = 4
==> If t is in meters, converting t to cm will give us u
Since 1m = 100cm
4m = u cm
1 × u = 100 × 4
u = 400cm
==> Vikki (v) and John shares $u in the ratio 7:3. Thus, Vikki (v) would receive the following:
v = ⁷/10 × $400
v = 0.7 × 400
v = $280