Answer:-(9 - 4i) =
Step-by-step explanation:
Given the complex number 9 - 4i, the additive inverse is the number that when added to the original number, would equate to zero. Another term this may be known as is the additive identity. The additive inverse is simply:
(a + bi) = -(a + bi)
Given: 9 - 4i
-(9 - 4i) = -9 + 4i
Answer:
x = 2.5 inches. Or
x = 5/2
Step-by-step explanation:
Length: 7 + 2x
Width: 5 + 2x
Note that you have to add x at each end of the picture and onto each part of the width.
The entire area is 120 square inches.
Formula
L*W = Area
(2x + 7)(2x + 5) = 120
Solution
4x^2 + 10x + 14x + 35 = 120 Subtract 120 from both sides. Add xs
4x^2 + 24x + 35 - 120 = 0
4x^2 + 24x - 85 = 0 Factor
(2x + 17)(2x - 5)
2x + 17 has no meaning. It will give - 8.5 which is not possible.
2x - 5 =0
2x = 5 Divide by 2
x = 5/2
x = 2.5
Note: I don't know which one the computer is looking for.
The first 3 are examples of the difference of 2 squares so you use the identity
a^2 - b^2 = (a + b)(a - b)
x^2 - 49 = 0
so (x + 7)(x - 7) = 0
so either x + 7 = 0 or x - 7 = 0
giving x = -7 and 7.
Number 7 reduces to 3x^2 =12, x^2 = 4 so x = +/- 2
Number 8 take out GCf (d) to give
d(d - 2) = 0 so d = 0 , 2
9 and 10 are more difficult to factor
you use the 'ac' method Google it to get more details
2x^2 - 5x + 2
multiply first coefficient by the constant at the end
that is 2 * 2 = 4
Now we want 2 numbers which when multiplied give + 4 and when added give - 5:- -1 and -4 seem promising so we write the equation as:-
2x^2 - 4x - x + 2 = 0
now factor by grouping
2x(x - 2) - 1(x - 2) = 0
(x - 2) is common so
(2x - 1)(x - 2) = 0
and 2x - 1 = 0 or x - 2 = 0 and now you can find x.
The last example is solved in the same way.
