# Thread: GR9 Math Exam Review

1. ## GR9 Math Exam Review

How would i find the x intercept of the following:

a) $y=-5$
b) $y=-3x+9$
c) $2x+3y-6=0$
d) $x=-4$

Thanks guys!

2. To find the x-intercept, set y to 0.

a) This one has no x-intercept, y is always -5 so it never crosses the x axis (which is defined by y=0).

b) 0=-3x+9
3x=9
x=3

So the x intercept is (3,0) or just 3.

c) 2x+3(0)-6=0
2x-6=0
2x=6
x=3

d) x is always equal to -4 regardless of y, so the x intercept is (-4,0).

Hope that helps.

3. How would i find the x intercept of the following:

a)
b)
c)
d)

Thanks guys!
hi
In a.) line is parallel to x-axis
In b.) and c.) put y=0
In d.) answer is in the question

4. Originally Posted by JD-Styles
To find the x-intercept, set y to 0.

a) This one has no x-intercept, y is always -5 so it never crosses the x axis (which is defined by y=0).

b) 0=-3x+9
3x=9
x=3

So the x intercept is (3,0) or just 3.

c) 2x+3(0)-6=0
2x-6=0
2x=6
x=3

d) x is always equal to -4 regardless of y, so the x intercept is (-4,0).

Hope that helps.

Thanks alot you guyz! I just have one more thing... what would be the y-int for d then?

5. Originally Posted by princevisram
Thanks alot you guyz! I just have one more thing... what would be the y-int for d then?
There is none. For the y intercept we need x=0 so it cannot intersect with x=-4.

6. Originally Posted by JD-Styles
There is none. For the y intercept we need x=0 so it cannot intersect with x=-4.
K Thanks... 1 more question

in y=mx+b form, how would you write y+3x=10?

would it be y=3x-10 or y=3x+10?

7. Originally Posted by princevisram
K Thanks... 1 more question

in y=mx+b form, how would you write y+3x=10?

would it be y=3x-10 or y=3x+10?
y=-3x+10

8. y=-3x+10

9. Originally Posted by JD-Styles
y=-3x+10
Now, what about $2t-d+10=0$? How do you know which one is y and which one is slope?

10. Originally Posted by princevisram
Now, what about $2t-d+10=0$? How do you know which one is y and which one is slope?
Depends on what t and d represent. I would assume that t stands for time and d stands for distance, in which case d would be you dependent variable (y).

y is always the variable that depends on the other one. For example if I had the equation p-3s-5=0, where p is the profit and s is the number of sales, well obviously my profit depends on the number of sales so p=y and s=x so I'd write p=3s+5.

Hope that all makes sense.

11. Originally Posted by JD-Styles
Depends on what t and d represent. I would assume that t stands for time and d stands for distance, in which case d would be you dependent variable (y).

y is always the variable that depends on the other one. For example if I had the equation p-3s-5=0, where p is the profit and s is the number of sales, well obviously my profit depends on the number of sales so p=y and s=x so I'd write p=3s+5.

Hope that all makes sense.
You are sooo amazing!