Answer:
3a - 2ab if a= 4 and b= 6 = -36
-7x + 5 = 8x -25 solve for x = 2
Explanation:
Evaluate 3 a - 2 a b where a = 4 and b = 6:
3 a - 2 a b = 3×4 - 2×4×6
3×4 = 12:
12 - 2×4×6
-2×4 = -8:
-8×6 + 12
-8×6 = -48:
-48 + 12
12 - 48 = -(48 - 12):
-(48 - 12)
| 4 | 8
- | 1 | 2
| 3 | 6:
Answer: -36
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Solve for x:
5 - 7 x = 8 x - 25
Subtract 8 x from both sides:
5 + (-7 x - 8 x) = (8 x - 8 x) - 25
-7 x - 8 x = -15 x:
-15 x + 5 = (8 x - 8 x) - 25
8 x - 8 x = 0:
5 - 15 x = -25
Subtract 5 from both sides:
(5 - 5) - 15 x = -5 - 25
5 - 5 = 0:
-15 x = -5 - 25
-5 - 25 = -30:
-15 x = -30
Divide both sides of -15 x = -30 by -15:
(-15 x)/(-15) = (-30)/(-15)
(-15)/(-15) = 1:
x = (-30)/(-15)
The gcd of -30 and -15 is -15, so (-30)/(-15) = (-15×2)/(-15×1) = (-15)/(-15)×2 = 2:
Answer: x = 2