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3 years ago

51pts! which expression represents a difference of squares?

Mathematics

2 answers:

m_a_m_a [10]3 years ago

7 0

Answer:

Step-by-step explanation:

81 - 49y^2 = (9 - 7y)(9 + 7y)

FOIL the equation.

(9 - 7y)(9 + 7y)

81 + 63y - 63y - 49y^2

81 - 49y^2

maw [93]3 years ago

7 0

Answer:Help me too!

Step-by-step explanation:

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Four baskets contain scented soaps. The baskets contain 9, 9, 11, and 15 soaps. If the soaps are divided evenly among the

Elis [28]

Answer:

Step-by-step explanation:

9+9+11+15 = 44

44/4 = 11!

3 0

3 years ago

Read 2 more answers

The sum of first three terms of a finite geometric series is -7/10 and their product is -1/125. [Hint: Use a/r, a, and ar to rep

Alchen [17]

Ooh, fun

geometric sequences can be represented as
$a_n=a(r)^{n-1}$
so the first 3 terms are
$a_1=a$
$a_2=a(r)$
$a_2=a(r)^2$

the sum is -7/10
$\frac{-7}{10}=a+ar+ar^2$
and their product is -1/125
$\frac{-1}{125}=(a)(ar)(ar^2)=a^3r^3=(ar)^3$

from the 2nd equation we can take the cube root of both sides to get
$\frac{-1}{5}=ar$
note that a=ar/r and ar²=(ar)r
so now rewrite 1st equation as
$\frac{-7}{10}=\frac{ar}{r}+ar+(ar)r$
subsituting -1/5 for ar
$\frac{-7}{10}=\frac{\frac{-1}{5}}{r}+\frac{-1}{5}+(\frac{-1}{5})r$
which simplifies to
$\frac{-7}{10}=\frac{-1}{5r}+\frac{-1}{5}+\frac{-r}{5}$
multiply both sides by 10r
-7r=-2-2r-2r²
add (2r²+2r+2) to both sides
2r²-5r+2=0
solve using quadratic formula
for $ax^2+bx+c=0$
$x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}$
so
for 2r²-5r+2=0
a=2
b=-5
c=2

$r=\frac{-(-5) \pm \sqrt{(-5)^2-4(2)(2)}}{2(2)}$
$r=\frac{5 \pm \sqrt{25-16}}{4}$
$r=\frac{5 \pm \sqrt{9}}{4}$
$r=\frac{5 \pm 3}{4}$
so
$r=\frac{5+3}{4}=\frac{8}{4}=2$ or $r=\frac{5-3}{4}=\frac{2}{4}=\frac{1}{2}$

use them to solve for the value of a
$\frac{-1}{5}=ar$
$\frac{-1}{5r}=a$
try for r=2 and 1/2
$a=\frac{-1}{10}$ or $a=\frac{-2}{5}$

test each
for a=-1/10 and r=2
a+ar+ar²= $\frac{-1}{10}+\frac{-2}{10}+\frac{-4}{10}=\frac{-7}{10}$
it works

for a=-2/5 and r=1/2
a+ar+ar²= $\frac{-2}{5}+\frac{-1}{5}+\frac{-1}{10}=\frac{-7}{10}$
it works

both have the same terms but one is simplified

the 3 numbers are $\frac{-2}{5}$ , $\frac{-1}{5}$ , and $\frac{-1}{10}$

6 0

3 years ago

There are 11.5 ounces of cereal in a container. Additional cereal is poured into the container at a rate of 2.25 ounces per seco

KatRina [158]

Answer:

13.........

Step-by-step explanation:

5 0

3 years ago

GIVING BRAINLEST TO THE PERSON WHO ANSWERS IT FIRST AND CORRECT!!

Kruka [31]

Answer:

read below explanation

Step-by-step explanation:

KEY= C;CAROL T;TINO B;BAXTER

inches: C=90 T=90 B=90

Feet: C=7.5 T=7.5 B=7.5

Yards C=2.5 T=2.5 B=2.5

5 0

3 years ago

Sabrina rides her bike 2 miles to school each day she leaves her house 7:30 and arrives at 7:50 What is Sabrina's average speed

MakcuM [25]

6 mph.

To find this, create a ratio.

2/20 = x/60

This will allow you to compare here time of twenty minutes to an hour in the same context.

Multiply 2 by 60 and divide by 20 to get the answer of 6 mph.

Thus, Sabrina's average speed in miles per hour is six miles per hour.

Hope this helps!

7 0

3 years ago