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3 years ago

A number is doubled and then increased by seven. The result is seventy-one. What is the original number?

Mathematics

1 answer:

marissa [1.9K]3 years ago

6 0

Answer:

i think its 43

Step-by-step explanation:

2 x X + 7 = 93

substract 7 from both sides then divide both sides by 2

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Solve the system of equations<br><br> a+s=560<br><br> 8a+3s=2905

Rasek [7]

Answer:

a=245 s=315

Step: Solve a+s=560 for a:

a+s=560

a+s=560(Add -s to both sides)

a=−s+560

Step: Substitute −s+560 for a in 8a+3s=2905:

8a+3s=2905

8(−s+560)+3s=2905

−5s+4480=2905(Simplify both sides of the equation)

−5s+4480=2905(Add -4480 to both sides)

−5s=−1575

−5s=−1575(Divide both sides by -5)

s=315

Step: Substitute 315 for s in a=−s+560:

a=−s+560

a=−315+560

a=245

4 0

2 years ago

1.) Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth .x squared minus 21 x equals n

Andrew [12]

Part 1
We are given $x^2-21x=-4x$ . This can be rewritten as $x^2-18x=0$ .
Therefore, a=1, b=-18, c=0.
Using the quadratic formula
$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}=\frac{-\left(-18\right)\pm \sqrt{\left(-18\right)^2-4\left(1\right)\left(0\right)}}{2\left(1\right)}$
$x=\frac{18\pm 18}{2}$

The values of x are
$x_1=\frac{18-18}{2}=0$
$x_2=\frac{18+18}{2}=18$

Part 2
Since the values of y change drastically for every equal interval of x, the function cannot be linear. Therefore, the kind of function that best suits the given pairs is a quadratic function.

Part 3.
The first equation is $y=x^2+2$ .
The second equation is $y=3x+20$ .

We have
$x^2+2=3x+20$
$x^2-3x-18=0$
Factoring, we have
$\left(x-6\right)\left(x+3\right)=0$
Equating both factors to zero.
$x_1-6=0\rightarrow x_1=6$
$x_2+3=0\rightarrow x_2=-3$

When the value of x is 6, the value of y is
$y=3\left(6\right)+20=38$

When the value of x is -3, the value of y is
$y=3\left(-3\right)+20=11$

Therefore, the solutions are (6,38) or (-3,11)

7 0

3 years ago

Heyy! please help posted picture of question

Bond [772]

A and D are true

good luck

4 0

3 years ago

Read 2 more answers

There are 3 blue marbles, 6 red marbles, 2 green marbles and 1 black marble in a bag. Suppose you select one marble at random. F

laila [671]

Answer:

For blue its 3/12 = 1/4 = 25%

For red it's 6/12= 1/2= 50%

For green 2/12= 1/6= 17%

For black 1/12= 8%

Step-by-step explanation:

All you have to do is add up all the marbles 3 + 6 + 2 + 1 = 12 and then you put the number of marbles for each color and divide it by 12 which gives you those percentages. I don't know if you wanted the answers in percentages or fractions so I gave you both . Good luck!!

4 0

3 years ago

A study concludes that 15 percent of all college students attend a gym class. Which of the following statements is true? 15 perc

yanalaym [24]

I think it is 15 percent is a statistic.
I am not 100% sure if it is right or not but I hope it helps!

4 0

3 years ago

Read 2 more answers