Answer:
Step-by-step explanation:
1) Eliminate parentheses:
0.1x +18.8 = -4 +2x
22.8 = 1.9x . . . . . . . . . add 4 - 0.1x
12 = x . . . . . . . . . . . . . divide by 1.9
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2) Eliminate parentheses:
-16 +4x = 0.8x +12.8
3.2x = 28.8 . . . . . . . . add 16 - 0.8x
x = 9 . . . . . . . . . . . . . .divide by 3.2
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<em>Comments on the solutions</em>
The expression we add in each case eliminates the constant on one side of the equation and the variable term on the other side. That leaves an equation of the form ...
variable term = constant
We choose to eliminate the smaller variable term (the one with the coefficient farthest to the left on the number line). Then the constant we eliminate is the on on the other side of the equation. This choice ensures that the remaining variable term has a positive coefficient, tending to reduce errors.
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You can work these problems by methods that eliminate fractions. Here, the fractions are decimal values, so are not that difficult to deal with. In any event, it is good to be able to work with numbers in any form: fractions, decimals, integers. It can save some steps.
X + x + 30 = 510
2x = 480
x = 240
there were 240 women and 270 men.
Answer:
30.285 m²
Step-by-step explanation:
C = 2πr
2 · π · 2
≈ 12.57
12.57 ÷ 2 = 6.285
10 - 2 = 8
8 · 4 ÷ 2
32 ÷ 2
16
2 · 4 = 8
6.285 + 8 + 16
30.285
Step-by-step explanation:
