first, write the equation of the parabola in the required form: 
(y - k) = a·(x - h)² 

Here, (h, k) is given as (-1, -16). 
So you have: 
(y + 16) = a · (x + 1)² 

Unfortunately, a is not given. However, you do know one additional point on the parabola: (0, -15): 

-15 + 16 = a· (0 + 1)² 
.·. a = 1 

.·. the equation of the parabola in vertex form is 
y + 16 = (x + 1)² 

The x-intercepts are the values of x that make y = 0. So, let y = 0: 

0 + 16 = (x + 1)² 
16 = (x + 1)² 

We are trying to solve for x, so take the square root of both sides - but be CAREFUL! 

± 4 = x + 1 ...... remember both the positive and negative roots of 16...... 

Solving for x: 
x = -1 + 4, x = -1 - 4 
x = 3, x = -5. 

Or, if you prefer, (3, 0), (-5, 0).

8 0

4 years ago

What is the equation of the line that passes through the point (-1, -7) and has a slope of 2?

slava [35]

Answer:

y=2x-5

Step-by-step explanation:

The slope-intercept form of an equation looks like y=mx+b. Where m is the slope and b is the y-intercept. The slope is already given to us, so m is 2.

To find b use the equation $b=y_1-m*x_1$ . So, to find the y-intercept use b=-7-(2*-1). This equals b=-5.