Find the conjugate and product of the following surds

2i + 9
-2i + 1
-3 + iy

The conjugate of 2i + 9 = -2i + 9

Product of (2i+9) and (2i+9)  is 36i + 77

Step-by-step explanation:

Given - 2i + 9

To find - Find the conjugate and product of the following surds

Proof -

We know that,

The sum and difference of two simple quadratic surds are said to be conjugate surds to each other.

To find a complex conjugate, simply change the sign of the imaginary part (the part with the i ).

So,

The conjugate of 2i + 9 = -2i + 9

Now,

Product of surd (2i+9) is

(2i+9)(2i+9) = 2i(2i) + 2i(9) + 9(2i) + 9(9)

                  = 4i² + 18i + 18i + 81

                  = -4 + 36i + 81          { because i² = -1 }

                  = 77 + 36i

⇒Product of (2i+9) and (2i+9)  is 36i + 77

answer: the price of one pound cabbage = $ 0.8

the point (10,8) represents that the cost of 10 pounds cabbage is $ 8

step-by-step explanation:

since, here is a proportional relation between the number of pounds of cabbage (x) and the price in dollars (y).

therefore, we can write,

⇒ y = k x

where k is the constant of proportionality.

now, point (5,4) is in the line.

thus, it will satisfies the above equation of line.

⇒ 4 = 5 k

⇒ k = 0.8

thus, the equation of the line is,

y = 0.8 x

a) for x = 1,

y = 0.8

therefore, the cost of one pound of cabbage is 0.8 dollars.

b) in the below graph (10,8) represents that the cost of 10 pounds of cabbage is 8 dollars.

yes the total will be same because in both of them the expression.is rearranged but their sign remains the same hence it hss just been shuffled