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3 years ago

Please help! Will mark brainliest

Mathematics

1 answer:

ser-zykov [4K]3 years ago

5 0

Answer:

Step-by-step explanation:

t1 = a1

t2 = a1 + d

t3 = a1 + 2d

The sum is t1 + t2 + t3 = a1 + a1 + d + a1 + 2d = 3a1 + 3d

Second question

t1 = a1

t2 = a1 + d

t3 = a1 + 2d

t4 = a1 + 3d

...

tn = a1 + (n - 1)*d

Sum = (a1 + a1 + (n- 1)*d) * n / 2

Sum = (2a1 + nd - d) * n / 2

Sum = (2a1*n + n^2*d - nd) / 2

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slope intercept form

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3y =2x+15

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3 years ago

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3 years ago

Two teachers purchase supplies for their classrooms.

inna [77]

Answer:

Cost of One Journal = $3.99

Cost of One pen = $0.59

Step-by-step explanation:

Let

Cost of One Journal = x

Cost of One pen = y

We can make equation from given statements.

Mr. Bowden purchases 18 journals and 40 pencils for $95.42.

$18x+40y=95.42$

Ms. Jacinto purchases 11 journals and 16 pencils for $53.33.

$11x+16y=53.33$

Now solving these equations to find the value of x

$18x+40y=95.42--eq(1)\\11x+16y=53.33--eq(2)$

Multiply eq(1) with 2 and eq(2) with 5

$36x+80y=190.84\\55x+80y=266.65\\-\:\:\:\:-\:\:\:\;\:\:\:\:\:\:\:-\\---------\\-19x=-75.81\\x=\frac{-75.81}{-19}\\x=3.99\\$

We get the value of x is: x=3.99

Now, putting value of x in equation 1 to find value of y.

$18x+40y=95.42\\18(3.99)+40y=95.42\\71.82+40y=95.42\\40y=95.42-71.82\\40y=23.6\\y=\frac{23.6}{40}\\y= 0.59$

So, we get the value of y: y = 0.59

Now, finding the costs:

Cost of One Journal = x = $3.99

Cost of One pen = y = $0.59

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3 years ago