Y - 4x = 7...y = 4x + 7
now sub 4x + 7 in for y in the other equation
2y + 4x = 2
2(4x + 7) + 4x = 2
8x + 14 + 4x = 2
12x = 2 - 14
12x = - 12
x = -1
y - 4x = 7
y - 4(-1) = 7
y + 4 = 7
y = 7 - 4
y = 3
solution is : (-1,3)
Answer:
<u>y = -x² + 4</u>
Step-by-step explanation:
The equation of the parabola in the vertex form is:
y = a (x-h)² + k
Where: (h,k) the coordinates of the vertex & a is a multiplier
The parabola has a vertex at ( 0,4 )
So, h = 0 , k = 4
∴ y = a (x-0)² + 4
∴ y = a x² + 4
The parabola passes through points ( 2,0 )
∴ 0 = a 2² + 4
∴ 4 a = -4 ⇒ a = -4/4 = -1
∴ y = -x² + 4
So, the equation of a parabola that has a vertex at ( 0,4 ) and passes through points ( 2,0 ) is <u>y = -x² + 4</u>
See the attached figure.
9^2 < 6^2 + 8^2
so its acute angled.
Y1 is the simplest parabola. Its vertex is at (0,0) and it passes thru (2,4). This is enough info to conclude that y1 = x^2.
y4, the lower red graph, is a bit more of a challenge. We can easily identify its vertex, which is (-4,0), and several points on the grah, such as (2,-3).
Let's try this: assume that the general equation for a parabola is
y-k = a(x-h)^2, where (h,k) is the vertex. Subst. the known values,
-3-(-4) = a(2-0)^2. Then 1 = a(2)^2, or 1 = 4a, or a = 1/4.
The equation of parabola y4 is y+4 = (1/4)x^2
Or you could elim. the fraction and write the eqn as 4y+16=x^2, or
4y = x^2-16, or y = (1/4)x - 4. Take your pick! Hope this helps you find "a" for the other parabolas.
