Find x-coordinate of Points A & B

[nycmathguy]

Set 1.5
Questions 42 & 43

See attachments.

In Exercises 42 and 43, determine the x-coordinates of the points A and B. (Each dashed line is parallel to a coordinate axis.)

 

[MathLover1]

42.
determine the x-coordinates of the points A and B

given line is
y=(1/2)x+1

the point A has y coordinate 1.5

then x coordinate will be

1.5=(1/2)x+1
1.5-1=(1/2)x
0.5=(1/2)x
1/2=(1/2)x
x=(1/2)/(1/2)
x=1=>the point A is at (1,1.5)

the point B has y coordinate 2.5
2.5=(1/2)x+1
2.5-1=(1/2)x
1.5=(1/2)x
3/2=(1/2)x
x=(3/2)/(1/2)
x=3=>the point B is at (3,2.5)


43.
given line is
y=(1/2)x^2

the point A has y coordinate 0.4

then x coordinate will be

0.4=(1/2)x^2
0.8=x^2
x=sqrt(0.8)-> we need positive value

x=0.89 =>the point A is at (0.89,0.4)

the point B has y coordinate 0.6

0.6=(1/2)x^2
1.2=x^2
x=sqrt(1.2)->and x coordinate is negative
x=-1.1 =>the point B is at (-1.1,0.6)

 

[nycmathguy]

42.
determine the x-coordinates of the points A and B

given line is
y=(1/2)x+1

the point A has y coordinate 1.5

then x coordinate will be

1.5=(1/2)x+1
1.5-1=(1/2)x
0.5=(1/2)x
1/2=(1/2)x
x=(1/2)/(1/2)
x=1=>the point A is at (1,1.5)

the point B has y coordinate 2.5
2.5=(1/2)x+1
2.5-1=(1/2)x
1.5=(1/2)x
3/2=(1/2)x
x=(3/2)/(1/2)
x=3=>the point B is at (3,2.5)


43.
given line is
y=(1/2)x^2

the point A has y coordinate 0.4

then x coordinate will be

0.4=(1/2)x^2
0.8=x^2
x=sqrt(0.8)-> we need positive value

x=0.89 =>the point A is at (0.89,0.4)

the point B has y coordinate 0.6

0.6=(1/2)x^2
1.2=x^2
x=sqrt(1.2)->and x coordinate is negative
x=-1.1 =>the point B is at (-1.1,0.6)

You make it look so easy. I couldn't figure out how to start a solution for either problem.