Answer:
i think -49
Step-by-step explanation:
if its not right than sorry
4a + 6b = 10
2a - 4b = 12...multiply by -2
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4a + 6b = 10
-4a + 8b = - 24 (result of multiplying by -2)
------------------add
14b = - 14
b = -14/14
b = -1
2a - 4b = 12
2a - 4(-1) = 12
2a + 4 = 12
2a = 12 - 4
2a = 8
a = 8/2
a = 4
so 12a = 12(4) = 48 <==
Answer:
1.8 × 10^10
Step-by-step explanation:
(7.2 × 10 = 72)
(72) ÷ (4 × 10^-9) = 1.8 × 10^10