12-4+5 x 2 = 20Where The parentheses should go?
1 answer:
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Answer:
see explanation
Step-by-step explanation:
x² + 3x + 7 = 5 ( subtract 5 from both sides )
x² + 3x + 2 = 0 ← in standard form
(x + 2)(x + 1) = 0 ← in factored form
Equate each factor to zero and solve for x ( zero product rule )
x + 2 = 0 → x = - 2
x + 1 = 0 ⇒ x = - 1
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x² - 2 = - 2x² + 5x ( subtract - 2x² + 5x from both sides )
3x² - 5x - 2 = 0 ← in standard form
(3x + 1)(x - 2) = 0 ← in factored form
Equate each factor to zero and solve for x
3x + 1 = 0 ⇒ 3x = - 1 ⇒ x = -
x - 2 = 0 ⇒ x = 2
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(x + 3)² + 4x = 0 ← expand left side using FOIL and simplify
x² + 6x + 9 + 4x = 0
x² + 10x + 9 = 0 ← in standard form
(x + 9)(x + 1) = 0 ← in factored form
Equate each factor to zero and solve for x
x + 9 = 0 ⇒ x = - 9
x + 1 = 0 ⇒ x = - 1