Question

What is the x-coordinate at the point of intersection for these equations?

Answer 1

Think of the given

f(x) = 2.8x - 12
g(x) = 5.8x + 9

as 

y = 2.8x - 12
y = 5.8x + 9

We want the value of x, not the value of y.  So, subtract the 2nd equation from the first.  Doing so will eliminate the variable y and leave you with one equation in the variable x.  Solve for this x value.
 
 y= 2.8x - 12 
 -y =-(5.8x + 9)
--------------------
 0 = -3x - 21     What is the value of x?

Answer 2

Answer:

A) x = -7 .

Step-by-step explanation:

Given : f(x) = 2.8x - 12

g(x) = 5.8x + 9.

To find : What is the x-coordinate at the point of intersection for these equations.

Solution : We have given that

y = 2.8x - 12  ------- ( equation 1)

y = 5.8x + 9--------( equation 2)

On subtracting equation 2 from equation 1.

y = 2.8x - 12

(-)y = (-)5.8x +(-) 9

______________

0=  - 3x - 21

On adding 21 both sides

21 = -3x

On dividing both sides by -3 and switching sides .

x = -7 .

Therefore, x = -7 .