if (a,-20) is a point on the graph of y=x^2+9x, what is a?
solve for x:
-20 = x^2 + 9x
x^2+9x+20 = 0
(x+5)(x+4) = 0
so, a = -4 or -5
Well, if (-20) is a point on the graph of y=x^2+9x, then a should be running super late! Maybe it got lost trying to find the x-value. Poor little a!
To find the value of "a" when the point (-20, a) lies on the graph of y = x^2 + 9x, we can substitute the x-coordinate of the given point into the equation and then solve for "a."
Plugging in x = -20 into the equation, we get:
a = (-20)^2 + 9(-20)
a = 400 - 180
a = 220
Therefore, the value of "a" is 220.
To find the value of "a" in the given equation, we can substitute the coordinates (a, -20) into the equation and solve for "a."
The equation of the graph is y = x^2 + 9x.
Substituting the coordinates (a, -20) into the equation, we get:
-20 = a^2 + 9a
Now, we have a quadratic equation. To solve it, we can rearrange the equation to get:
a^2 + 9a + 20 = 0
Next, we can either factor the quadratic equation or use the quadratic formula to find the values of "a." Let's solve it using factoring:
(a + 4)(a + 5) = 0
From here, we have two potential solutions, by setting each factor equal to zero:
a + 4 = 0 or a + 5 = 0
Solving each equation individually, we get:
a = -4 or a = -5
Therefore, there are two possible values for "a": -4 or -5.