Answer & Step-by-step explanation:
2a - b : 2a + b = 1 : 2
2a - b = 1
- Elimination
2a + b = 2
-b - (b) = -1
-2b = -1
b = 0.5
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2a + b = 2 Substitution
2a + 0.5 = 2
2a = 1.5
a = 0.75
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a:b
0.75 : 0.5
or
3/4 : 1/2
Hope this helps!!!