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Paladinen [302]
3 years ago
10

Solve for x. x + 3x + 5 =21

Mathematics
2 answers:
timurjin [86]3 years ago
4 0

Answer:

x=4

Step-by-step explanation:

In order to solve for x, we must isolate x on one side of the equation.

x+3x+5=21

First, combine like terms. x and 3x are both terms with variables, and can be combined.

(x+3x) + 5=21

4x + 5=21

5 is being added to 4x. The inverse of addition is subtraction. Subtract 5 from both sides of the equation.

4x+5-5= 21-5

4x= 16

x is being multiplied by 4. The inverse of multiplication is division. Divide both sides by 4.

4x/4=16/4

x= 16/4

x=4

Let's check our solution. Plug 4 in for x and solve.

x+3x+5=21

4+3(4)+5=21

4+12+5=21

16+5=21

21=21

This solution checks out, so we know our answer is correct.

x is equal to 4, x=4.

lutik1710 [3]3 years ago
3 0

Answer:

x = 4

Step-by-step explanation:

x + 3x + 5 = 21

4x + 5 = 21

4x = 21 - 5

4x = 16

x = 16/4

x = 4

verify:

4 + 3*4 + 5 = 21

4 + 12 + 5 = 21

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Step-by-step explanation:

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A bag contains 21 red marbles, 4 white marbles, and 3 gray marbles. Do you randomly pick out a marble recorded color and put it
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Step-by-step explanation:

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then you find how many are white or gray

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2 years ago
The 10th term in the sequence is 2560 what is the 11th term in the sequence
joja [24]

Full Question:

The 4th term of a g.p. is 40 and the 10th term in the sequence is 2560, what is the 11th term in the sequence ?

Answer:

the 11 the term is 5120

Step-by-step explanation:

Given

Geometry Progression

4th term = 40

10th term = 2560

Required

11 term.

The nth term of a geometric sequence is calculated as follows

Tₙ = arⁿ⁻¹

For the 4th term, n = 4 and Tₙ = 40

Substitute these in the given formula; this gives

40 = ar⁴⁻¹

40 = ar³. --;; equation 1

For the 10th term, n = 10 and Tₙ = 2560

Substitute these in the given formula; this gives

2560 = ar¹⁰⁻¹

2560 = ar⁹. --;; equation 2

Divide equation 2 by 1. This gives

2560/40 = ar⁹/ar³

64 = r⁹/r³

From laws of indices

64 = r⁹⁻³

64 = r⁶

Find 6th root of both sides

(64)^1/6 = r

r = (2⁶)^1/6

r = 2

Substitute r = 2 in equation 1

40 = ar³. Becomes

40 = a * 2³

40 = a * 8

40 = 8a

Divide both sides by 8

40/8 = 8a/8

5 = a

a = 5.

Now, the 11 term can be solved using Tₙ = arⁿ⁻¹ where n = 11

So,

Tₙ = arⁿ⁻¹ becomes

Tₙ = 5 * 2¹¹⁻¹

Tₙ = 5 * 2¹¹⁻¹

Tₙ = 5 * 2¹⁰

Tₙ = 5 * 1024

Tₙ = 5120.

Henxe, the 11 the term is 5120

5 0
2 years ago
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