Question

Point M is the midpoint of FG. Can the value of variable a be determined? Explain.

a
G(24,30+3)
M(3,5)
F[b+1 a+2)
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. To determine the value of a, set up and solve a system of equations in two variables. The value of a is
B. To determine the value of a, set the x- and y-coordinates of G and Fequal to each other and solve for a The value of a is
C. To determine the value of a, divide each coordinate of M by 2. Then add each quotient to the x-and y-coordinates of M. The value of a is
D. Not enough information is given for the value of a to be determined.

Answer 1

A. To determine the value of a, set up and solve a system of equations in two variables. The value of a is 2

Explanation:

Given the coordinates F(b+1, a+2, M(3,5) and G(2a, 3b+3), if M is the midpoint of F and G then, to get the value of a and b we will use the formula for calculating the midpoint a shown;

M(X, Y) = (x₁+x₂/2, y₁+y₂/2)

X = x₁+x₂/2 and Y = y₁+y₂/2

From the given coordinates x₁ = b+1, y₁ = a+2, x₂ = 2a, y₂ = 3b+3, X = 3 and Y = 5

Substituting the given parameters into the formula, we can form up a simultaneous equation and get the value of a.

To determine the value of a, set up and solve a system of equations in two variables

For the X coordinates;

X = x₁+x₂/2

3 = b+1+2a/2

6 = 2a+b+1

2a+b = 5 ............... 1 * 1

For the Y coordinates;

5 = a+2+3b+3/2

cross multiply

10 = a+2+3b+3

collect like terms

a+3b = 10-2-3

a+3b = 5 ........ 2 * 2

Solving the resulting simultaneous equation to get the value of a

multiply equation 1 by 1 and 2 by 2 to have the resulting equations;

2a+b = 5 ...........3

2a +6b = 10.......... 4

subtract 3 from 4

(2a-2a)+(b - 6b) = 5-10

0-5b = -5

b = -5/-5

b = 1

substitute b =1 into equation 1 to get a;

2a + b = 5

2a + 1 = 5

2a = 5-1

2a = 4

a = 2

From the calculation above it is seen that the value of variable a can be determined and it is equivalent to 2