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3 years ago

Solve using elimination. -7x – 5y = -4 7x + 9y = -4

1 answer:

5 0

-7x-5y=-47x+9y=-4

combine like terms to cross out the 7x
solve for y, to get -2
plug it back in to one of the equations and x is 2

y=-2
x=2

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A worker takes 3 hours to do a job. A new worker takes 5 hours. How long does it

Mariulka [41]

time taken by a worker= 1/3 hours

time taken by the new worker= 1/5 hours

time taken to complete the work if they work together

= 1/3 + 1/5

= 5+3/15

=8/15

=15/8 hours

6 0

3 years ago

Solve for x.<br> x + 7/6 = 2x - 7/6

storchak [24]

X + 7/6 = 2x - 7/6

x + 7/6 (-7/6) = 2x - 7/6 - (7/6)

x = 2x - 14/6

x (-2x) = 2x (-2x) - 14/6

-x = -14/6

x = 14/6 or 2.33

x = 2.33

hope this helps

4 0

3 years ago

Find all the missing elements:

Evgesh-ka [11]

Answer:

a=10.8; c=4.3

Step-by-step explanation:

The sum of all the angles in a triangle is 180 degrees.

Two of the angles are given as 40 deg and 120 deg.

Subtract the measures of both from the sum to get the last angle:

180-40-120=20; ∠C=20°

Using Law of Sines: $\frac{a}{sinA}=\frac{b}{sinB}=\frac{c}{sinC}$

$\frac{a}{sin120}=\frac{8}{sin40}; a=\frac{8*sin120}{sin40}; a=10.77837084$

$\frac{c}{sin20}=\frac{8}{sin40}; a=\frac{8*sin20}{sin40}; c=4.25671109$

8 0

3 years ago

There are 45 books on a bookshelf. if 9 are mystery books, what percent of the books on the bookshelf are mystery books?

Kay [80]

20%, just calculate the fraction of mystery books and multiply that by 100 %

4 0

4 years ago

How much more would $1000 earn in 5 years in an account compounded continuously than an account compounded quarterly if the inte

choli [55]

$\bf ~~~~~~ \textit{Compounding Continuously Interest Earned Amount}\\\\
A=Pe^{rt}\qquad 
\begin{cases}
A=\textit{accumulated amount}\\
P=\textit{original amount deposited}\to& \$1000\\
r=rate\to 3.7\%\to \frac{3.7}{100}\to &0.037\\
t=years\to &5
\end{cases}
\\\\\\
A=1000e^{0.037\cdot 5}\implies A=1000e^{0.185}\\\\
-------------------------------\\\\$

$\bf ~~~~~~ \textit{Compound Interest Earned Amount}
\\\\
A=P\left(1+\frac{r}{n}\right)^{nt}
\quad 
\begin{cases}
A=\textit{accumulated amount}\\
P=\textit{original amount deposited}\to &\$1000\\
r=rate\to 3.7\%\to \frac{3.7}{100}\to &0.037\\
n=
\begin{array}{llll}
\textit{times it compounds per year}\\
\textit{quarterly, thus four}
\end{array}\to &4\\
t=years\to &5
\end{cases}
\\\\\\
A=1000\left(1+\frac{0.037}{4}\right)^{4\cdot 5}\implies A=1000(1.00925)^{20}$

compare both amounts.

8 0

3 years ago