Need Help

[Dominic]

I need help solving this problem.

Determine the x-intercept and y-intercept of the graph of each equatiion:

(15) 2x+4y=8

 

[Guest]

The x-intercept is the value of x when y = 0. So let y = 0, and solve for x.

The y-intercept is the value of y when x = 0. So let x = 0, and solve for y.

 

[Dominic]

2x+4y=8

2x+4(0)=8

2x=8/2

x=4

 

[tkhunny]

2x + 4y = 8

One might first simplify things. I see a common factor of 2.

x + 2y = 4

Have you met the "Intercept Form"? Divide by 4

(x/4) + (y/2) = 1 <== Those intercepts are staring at you in the denominators.

 

[Guest]

2x+4(0)=8

2x=8/2

What did you do here? Looks like you divided the right hand side by 2, but not the left.

2x=8/2

x=4

What did you do here? Looks like you divided the left hand side by 2, but not the right.

You always have to do the same thing to both sides of the equation at the same time. In this case, your mistakes happened to cancel each other out and lead to the right answer, but your third equation is false. It is not true that 2x = 8/2. 2x = 2(4) = 8, and 8/2 = 4.