Answer:
<h2>x =
-2+i√5 and -2i-√5</h2>
Step-by-step explanation:
The general form of a quadratic equation is ax²+bx+c = 0
Given the quadratic equation x²+4x+9=0 in its standard form, on comparing with the general equation we can get the value of the constant a, b and c as shown;
ax² = x²
a = 1
bx = 4x
b = 4
c = 9
The quadratic formula is given as x = -b±√(b²-4ac)/2a
Substituting the constant;
x = -4±√(4²-4(1)(9))/2(1)
x = -4 ±√(16-36)/2
x = -4±√-20/2
x = -4±(√-1*√20)/2
Note that √-1 = i
x = -4±(i√4*5)/2
x = (-4±i2√5)/2
x = -4/2±i2√5/2
x = -2±i√5
The solution to the quadratic equation are -2+i√5 and -2i-√5
Answer: The correr solution is 
Step-by-step explanation:
Since the steps in Lin's solution are not shown, we are not able to find her erros. However, we can solve it step by step and find the correct result:

Firstly, in the left part of the equation we have to multiply
by the numbers inside the parenthesis; and in the right side we have to solve first what is inside the parenthesis:

Adding similar terms in the left side and multiplying
by the number inside the parenthesis in the right side:

Isolating
:
This is the correct solution
Answer:
88 inches
Step-by-step explanation:
Diameter is 2 times the radius (r) so divided 28 by 2 to get 14 as the radius.
Plug this in:
2π14
28π
87.964
88
Answer:
The number x is -3
Therefore x=-3
Step-by-step explanation:
Given problem is "Three added to eight times a number is the same as three times the value of two times the number -1"
Let x be the number
It can be written as

( applying the distributive property )


subtracting (6x-3) on both sides we get


( ading the like terms )


Therefore x=-3
The number x is -3