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.
Answer:
10 cuadrados
Step-by-step explanation:
Si uno de los lados de rectangulo es de 4cm entonces el lado parallelo tambien es de 4cm. Eso nos da 8cm del perimetro y nos quedan los otros dos lados que tienen la misma medida. Entonces dividimos el resto del perimetro por 2.
28 - 8 = 20cm
20cm / 2cm = 10cm
Ahora que tenemos todas las medidas podemos multiplicar el largo por el ancho para calcular el area del rectangulo
10cm * 4cm = 40
el cuadrado de 2cm tendra un area de
2cm * 2cm = 4
Ahora simplemente dividimos el area del rectangulo por el area del cuadrado para saber cuantos cuadrados necesitamos para armar ese rectangulo
40 / 4 = 10 cuadrados
