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svp [43]
3 years ago
9

(3a+2.5b)^2=9a^2+6.25b^2+* Please help before Thursday

Mathematics
1 answer:
Anon25 [30]3 years ago
5 0

Step-by-step explanation:

We have (x + y)² = (x + y)(x + y) = x² + 2xy + y².

Let x be 3a and y be 2.5b.

Therefore (3a + 2.5b)²

= (3a)² + 2(3a)(2.5b) + (2.5b)²

= 9a² + 15ab + 6.25b².

Hence the '*' sign should be replaced with 15ab.

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You worked theses hours this week: 1 1/2 , 2 3/4, 3 3/4, 5 1/2
alukav5142 [94]

Answer: 13.5 hours.

I got the answer by simply adding up the integers to start with.

Integers = 1, 2, 3 and 5.

The integers added up equal to 11.

Next we add up the remaining fractions.

Fractions = 1/2, 3/4, 3/4 and 1/2.

We can add up 1/2 and 1/2 to equal 1, and 3/4 and 3/4 to make 1.5.

1 + 1.5 = 2.5          

Finally, we add up the answer for the integers and the fractions together, (11 + 2.5) which equals 13.5.

Our answer is 13.5 hours.      

(Not sure why the answer isn't in the choices)                          

6 0
3 years ago
A population of bacteria is initially 6000. After three hours the population is 3000. If this rate of decay continues, find the
serious [3.7K]

Answer:

The equation is A=6000e^{-0.23t}  at a rate of -23%.

Step-by-step explanation:

Decay can be represented by the equation A=A_0e^{rt}. We can find the rate at which it decays by using t=3 hours and A=3000. This means A_0=6000 in this context.

A=A_0e^{rt}\\3000=6000e^{r(3)}

0.5=e^{(24.5)r}

After substituting, we divided by 6000 to each side to get 0.5 on the left. Now to solve for r, we will take the natural log of both sides and use log rules to isolate r.

ln 0.5=ln e^{(3)r}\\ln 0.5=3r (ln e)\\\frac{ln0.5}{3} =r

We know lne=1 so we were able to cancel it out and divide both sides by 3.

We solve with a calculator \frac{ln0.5}{3} =r\\-0.23=r

We change -0.23 into a percent by multiplying by 100 to get -23% as the rate.

The equation is A=6000e^{-0.23t}


5 0
3 years ago
Which statement best describes the equation x^5+x^3-14=0
oee [108]
<span>The equation is not quadratic in for because it cannot be written as a second degree polynomial</span>
5 0
3 years ago
HELP ASAP!!! WILL MARK BRAINLIEST!
Levart [38]

Answer:

outlier

Step-by-step explanation:

6 0
2 years ago
If ab is 2x+3 bc is 3x+5 and ac is 38 what is the value of x
ohaa [14]

Answer:

x would equal 8. because you would add AB and BC together and set it equal to AC

Hoped I helped

Can I get a brainliest

3 0
3 years ago
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