Jawaban:

Kesimpulan yang diperoleh:

• c = -28
• Persamaan yang dimaksud x² + 3x -28 = 0
• Akar lainnya x = -7

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Penjelasan dengan langkah-langkah:

Given that

"One of the values of x from the quadratic equation x² + 3x + c = 0 is 4"

It means x = 4

Find the value of cby substituting the value of x from the equationx² + 3x + c = 0 with 4

4² + 3*4 + c = 0

16 + 12 + c = 0

c = -16 - 12

c = -28

Therefore the value of c (the constant) is -28, meaning that the suitable quadratic equation where one of the values of x is 4 is

x² + 3x -28 = 0

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Find another value of x from the quadratic equation x² + 3x -28 = 0

x² + 3x -28 = 0

x² - 4x + (-28/-4)x - 28 = 0

x² - 4x + 7x - 28 = 0

x(x-4) + 7(x-4) = 0

(x+7)(x-4) = 0

x-4 = 0 ; maka x = 4

x+7 = 0 ; maka x = -7

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Kalau pake bahasa Indonesia:

Diketahui:

"Salah satu akar dari persamaan kuadrat x² + 3x + k = 0 adalah 4"

Artinya x = 4

Cari nilai kdengan menyubstitusi nilai x dari persamaanx² + 3x + k = 0 dengan 4

4² + 3*4 + k = 0

16 + 12 + k = 0

k = -16 - 12

k = -28

Oleh karena itu konstanta dalam persamaan tersebut adalah -28, dan persamaan kuadrat dimana salah satu akarnya 4 adalah:

x² + 3x -28 = 0

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Cari akar yang lain selain 4, dari persamaan kuadrat x² + 3x -28 = 0

x² + 3x -28 = 0

x² - 4x + (-28/-4)x - 28 = 0

x² - 4x + 7x - 28 = 0

x(x-4) + 7(x-4) = 0

(x+7)(x-4) = 0

x-4 = 0 ; maka x = 4

x+7 = 0 ; maka x = -7

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<(7o7)>