# Without plotting the function y = f (x), find the coordinates of its intersection

**Without plotting the function y = f (x), find the coordinates of its intersection points with the Ox and Oy axes: A) f (x) = 9x + 12 B) f (x) = – 4x + 22 B) f (x ) = 7x-28**

When the function graph intersects the Ox axis (abscissa), the y coordinate is 0. When the function intersects the Oy axis (ordinate), the x coordinate is 0.

A) f (x) = 9x + 12.

Intersection with the Ox axis:

9x + 12 = 0;

9x = – 12;

x = – 12/9 (in proportion);

x = – 4/3.

Point coordinates (- 4/3; 0).

Oy-axis intersection:

y = 9 * 0 + 12;

y = 12.

Point coordinates (0; 12).

B) f (x) = – 4x + 22.

Intersection with the Ox axis:

– 4x + 22 = 0;

– 4x = – 22;

x = – 22 / (- 4) (in proportion);

x = 11/2;

x = 5.5.

Point coordinates (5,5; 0).

Oy-axis intersection:

y = (- 4) * 0 + 22;

y = 22.

Point coordinates (0; 22).

B) f (x) = 7x – 28.

Intersection with the Ox axis:

7x – 28 = 0;

7x = 28;

x = 28/7 (in proportion);

x = 4.

Point coordinates (4; 0).

Oy-axis intersection:

y = 7 * 0 – 28;

y = – 28.

Point coordinates (0; – 28).