All categories

3 years ago

What is the first term in the sequence for which d = -2 and a7 = 3?

Mathematics

1 answer:

lana66690 [7]3 years ago

7 0

Answer:

First term is 15

Step-by-step explanation:

Given data:

$a_{7} =3\\d=-2$

Now,

$a+6d=3.....(1)\\a_{n} =a+(n-1)d\\\\\\From equation (1)\\a+6(-2)=3\\a-12=3\\a=12+3\\a=15$

Therefore first term a =15

Correct option is (c)

You might be interested in

Determine whether the lines are parallel, intersect, or coincide. x-5y=0, y+1=1/5(x+5)

MAXImum [283]

Answer-

The lines are two coinciding lines or the same lines.

Solution-

The given line equations are

the first one,

$\Rightarrow x-5y=0$

the second one,

$\Rightarrow y+1=\dfrac{1}{5}(x+5)\\\\\Rightarrow 5y+5=x+5\\\\\Rightarrow 5y=x\\\\\Rightarrow x-5y=0$

As we know two line equations $A_1x+B_1y+C_1=0$ and $A_2x+B_2y+C_2=0$ will be,

Parallel if, $\dfrac{A_1}{A_2}=\dfrac{B_1}{B_2}$
Coincide if, $\dfrac{A_1}{A_2}=\dfrac{B_1}{B_2}=\dfrac{C_1}{C_2}$
Intersect if, $\dfrac{A_1}{A_2}\neq \dfrac{B_1}{B_2}$

As here,

$\Rightarrow \dfrac{A_1}{A_2}=\dfrac{B_1}{B_2}=\dfrac{C_1}{C_2}$

$\Rightarrow \dfrac{1}{1}=\dfrac{-5}{-5}$

(C₁ and C₂ aren't considered as they are 0)

Therefore, the lines are two coinciding lines or the same lines.

4 0

3 years ago

The computer club spent $2,565 on mouse pads. The me never plan to sell the nous pads during the book fair. If they charge $9.50

Lapatulllka [165]

The answer is 270 because 2,565/9.5=270 hope this helps!

8 0

3 years ago

A refund of $3.15 on a $8.64 bill

Varvara68 [4.7K]

8.64 - 3.15 = $5.49 if this is what you are asking

5 0

4 years ago

Read 2 more answers

. can someone help pls

disa [49]

Answer:

The answer is 3,906.25

Step-by-step explanation:

All you have to do is divide 15,625 by 4! :)

6 0

3 years ago

I need help on this problem can someone help -8 (y - 86) = -48

exis [7]

Answer:

y=92

Step-by-step explanation:

Divided both sides by the numeric factor on the left side, then solve.

y = 92

6 0

3 years ago