Suppose the x

-intercept of f(x) is (p,0) and the x
-intercept of g(x) is (q,0) . What is the value of p+q
?



Two lines are graphed on a four quadrant coordinate plane. The x-axis and the y-axis go from negative 10 to 10 in increments of 1. One line, labeled f left parenthesis x right parenthesis, passes through (negative 4, 6) and (0, 9). The other line, labeled g left parenthesis x right parenthesis, passes through (negative 7, 6) and (0, 4).

(1 point)
Responses

−1
negative 1

1
1

0
0

2

1 answer

To find the x-intercept of a line, we need to find the value of x when y equals 0.

For f(x), the x-intercept is when y equals 0. We can set y equal to 0 in the equation of the line and solve for x:

0 = mx + b

0 = m(p) + b [since the x-intercept is (p,0)]

0 = mp + b

b = -mp

Now we can substitute the coordinates of the point (0,9) into the equation to find the value of m:

9 = m(0) + b

9 = 0 + b

b = 9

So the equation of f(x) is y = mp + 9. Substituting the coordinate (-4,6) into the equation:

6 = m(-4) + 9

6 = -4m + 9

-3 = -4m

m = 3/4

Therefore, the equation of f(x) is y = (3/4)x + 9.

Using the same process for g(x), we can find the equation of g(x) to be y = (2/7)x + 6.

To find the x-intercepts of f(x) and g(x), we can set y equal to 0 and solve for x:

0 = (3/4)x + 9

(3/4)x = -9

x = -36/3

x = -12

So the x-intercept of f(x) is (-12,0).

0 = (2/7)x + 6

(2/7)x = -6

x = -42/2

x = -21

So the x-intercept of g(x) is (-21,0).

Therefore, p + q = -12 + (-21) = -33.