Let a=1,-3,2 and b= -1,3,-2 find a-3b
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Considering the definition of map and scale, an actual distance of 269.59 km represent a scale distance of 5.7 inches .
<h3>Definition of map and scale</h3>A map is a representation of a place, at a size smaller than the real size.
The scale of a cartographic representation is the relationship of similarity between the real dimensions of the geographical space represented and those of its image on the map. That is, the scale is defined as the proportionality relationship that exists between a distance measured on the ground and its corresponding measurement on the map.
One way to represent the scale is by a fraction, which indicates the proportion between the distance on a map and its corresponding distance in reality:
In this case, you know that a scale distance of 3.5 inches on a map represent an actual distance of 175 km.
To know the real distance that represents a scale distance of 5.7 inches, as the scale ratio is the same as in the previous case, it is expressed:
Solving:
×distance in reality= 5.7 inches
distance in reality=
<u><em>distance in reality= 269.59 km</em></u>
In summary, an actual distance of 269.59 km represent a scale distance of 5.7 inches .
Learn more about map and scale:
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A second degree polynomial function has the general form:
, where 
.
The leading coefficient is a, so we have a=-1.
5 is a double root means that :
i) f(5)=0,
ii) the discriminant D is 0, where
.
Substituting x=5, we have
f(5)=a(5)^2+b(5)+c,
and since f(5)=0, and a is -1 we have:
0=-25+5b+c
thus c=25-5b.
By ii)
.
Substituting a with -1 and c with 25-5b we have:
Finally we find c: c=25-5b=25-50=-25
Thus the function is
Remark: It is also possible to solve the problem by considering the form
directly.
In general, if a quadratic function has leading coefficient a, and has a root r of multiplicity 2, then its form is
The leading coefficient is a, so we have a=-1.
5 is a double root means that :
i) f(5)=0,
ii) the discriminant D is 0, where
Substituting x=5, we have
f(5)=a(5)^2+b(5)+c,
and since f(5)=0, and a is -1 we have:
0=-25+5b+c
thus c=25-5b.
By ii)
Substituting a with -1 and c with 25-5b we have:
Finally we find c: c=25-5b=25-50=-25
Thus the function is
Remark: It is also possible to solve the problem by considering the form
In general, if a quadratic function has leading coefficient a, and has a root r of multiplicity 2, then its form is