<span>-4x^2+3x+1=0
D = b</span>² - 4ac = 3² - 4 * (-4) * 1 = 9 + 16 = 25
D>0 ⇒ <span>this equation has two solutions.</span>
Answer:
Part 1) 
Part 2) 
Part 3) 
Step-by-step explanation:
we know that
The equation of the line into slope intercept form is equal to

where
m is the slope
b is the y-intercept
Part 1) we have
(10,-3) (5,-2)
<u><em>Find the slope</em></u>
The formula to calculate the slope between two points is equal to
substitute
<em>Find the value of b</em>
we have

substitute in the equation
and solve for b



substitute

Part 2) we have
(6,2) (7,5)
<u><em>Find the slope</em></u>
The formula to calculate the slope between two points is equal to
substitute
<em>Find the value of b</em>
we have

substitute in the equation
and solve for b



substitute

Part 3) we have
(4,4) (-7,4)
<u><em>Find the slope</em></u>
The formula to calculate the slope between two points is equal to
substitute
This is a horizontal line (parallel to the x-axis)
The y-intercept b is equal to the y-coordinate
<em>therefore</em>
The equation of the line is

Answer:
16.2
Step-by-step explanation:
The angle internal to the triangle at B is the supplement of the one shown, so is 65°. That is equal to the angle internal to the triangle at D. Since the vertical angles at C are congruent, the two triangles are similar by the AA theorem.
Corresponding sides of similar triangles are proportional, so we can write the proportion shown in the attachment:
BC/FC = DC/AC
BC = FC(DC/AC) = 21.6(7.2/9.6)
BC = 16.2 . . . . matches the first choice
Vertex form:
y-k=a(x-h)^2
h=-2,k=-20,y=-12 when x=0
thus;
-12+20=a(0+2)^2
8=4a
a=2
Equation:
y+20=2(x+2)^2
y+20=2(x^2+4x+4)
f(x)=2(x^2+4x+4)-20
f(x)=2x^2+8x+8-20
f(x)=2x^2+8x-20