I only know the substitutional method so I am going to give you the answers.
1. (remember I am only using the substitutional method, I am doing the method wrong...)
x + y = 10, 3x - y = 2, 5(3x-y) = 5(2), 15x - 5y = 10, 15x -5y = x + y, 14x = 6y, x = 3/7 y , 3/7 y + y = 10, 10/7y = 10, 10 y = 70, y = 7, 14x = 42. x =3
y = 7, x = 3
2. What I know:
x + y = 6
x + 2x = 6
3x = 6
x = 2, y =4
3. I am using a video to help me remember.
x = 2y + 3 2x + 3y = -3.
-3 = 2y - x -3 = 3y + 2x
0 = - y + 3x, y = 3x
x = 2(3x) + 3, x = 6x + 3
-5x = 3, x = -3/5
y = 3(-3/5)
y = -9/5, x = -3/5
Step-by-step explanation:
the answer................
The correct answer is: [A]: " 2x³ + 7x² + 12x − 8 " .
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Explanation:
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Given:
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" (x² + 4x + 8) (2x − 1) " ; Find the product:
↔ " (2x − 1) (x² + 4x + 8) " ;
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Note: " (a + b) (c + d + e) = ab + ad + ae + bc + bd + ae " .
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→ " (2x − 1) (x² + 4x + 8) =
(2x * x²) + (2x * 4x) + (2x *8) + (-1 * x²) + (-1 * 4x) + (-1 * 8) ;
= 2x³ + 8x² + 16x + (-1x²) + (-4x) + (-8) ;
= 2x³ + 8x² + 16x − x² − 4x − 8) ;
→ Combine the "like terms" :
+ 8x² − x² = + 7x² ;
+ 16x − 4x = + 12x ;
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And rewrite the expression:
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→ " 2x³ + 7x² + 12x − 8 " ;
→ which is: Answer choice: [A]: " 2x³ + 7x² + 12x − 8 " .
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Answer:
-(sqrt2)
Step-by-step explanation:
