Kuis 100/2 Points dari Stingray:[Spesial 800 like jawaban Sy].[Gampang aja]

Jawaban:

1) Barisan aritmatika

U800 = 3.998

S800 = 1.600.400

2) SPLDV

maka x/y = 1

Penjelasan dengan langkah-langkah:

1) Barisan aritmatika

Diketahui :

a (suku pertama) = 3

b (beda) = 5

Ditanya :

. U800 = …

. S800 = …

Dijawab :

. U800 (n = 800)

Un = a + (n – 1)b

U800 = 3 + (800 – 1)5

U800 = 3 + 799 × 5

U800 = 3 + 3.995

U800 = 3.998

. S800 (n = 800)

Sn = n/2 {2a + (n – 1)b}

S800 = 800/2 {2 × 3 + (800 – 1)5}

S800 = 400 (6 + 799 × 5)

S800 = 400 (6 + 3.995)

S800 = 400 × 4.001

S800 = 1.600.400

2) SPLDV

3x + 5y = 800 … (1) [× 5] 15x + 25y = 4.000

5x + 3y = 800 … (2) [× 3] 15x + 9y = 2.400

————————- –

16y = 1.600

y = 1.600 ÷ 16

y = 100

substitusi y = 100 ke (2)

5x + 3 × 100 = 800

5x + 300 = 800

5x = 800 – 300

5x = 500

x = 500 ÷ 5

x = 100

maka, nilai x / y = 100 / 100 = 1

Jawab:

1) U800 = 3998

S800 = 1600400

2) 1

Penjelasan dengan langkah-langkah:

Soal 1

Un = a + (n – 1)b

Maka,

U800 = 3 + (800 – 1)5

= 3 + (799)5

= 3 + 3995

= 3998

Sn = n/2 . (a + Un)

Maka,

S800 = 800/2 . (3 + 3998)

= 400(4001)

= 1600400

Soal 2

3x + 5y = 800 ⇔ 15x + 25y = 4000 …. (i)

5x + 3y = 800 ⇔ 15x + 9y = 2400 …. (ii)

Eliminasi (i) dan (ii)

15x + 25y = 4000

15x + 9y = 2400

______________-

16y = 1600

y = 100

Substitusi nilai y ke (ii)

5x + 3y = 800

5x + 3(100) = 800

5x + 300 = 800

5x = 500

x = 100

Jadi, x/y = 100/100 = 1