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A student multiplies (4+5i) (3-2i) incorrectly and obtains 12-10i what is the students mistakes

Rufina [12.5K]

Answer:

1. In the multiplication of the imaginary parts, the student forgot to square of i. OR

2. The student has only multiplied the real parts and the imaginary parts.

Correct value $=22+7i$ .

Step-by-step explanation:

The given expression is

$(4+5i)(3-2i)$

A student multiplies (4+5i) (3-2i) incorrectly and obtains 12-10i.

Student's mistake can be either 1 or second:

1. In the multiplication of the imaginary parts, the student forgot to square of i.

2. The student has only multiplied the real parts and the imaginary parts.

$(4+5i)(3-2i)=4\times 3+5\times (-2)i=12-10i$

Which is not correct. The correct steps are shown below.

Using distributive property, we get

$4(3-2i)+5i(3-2i)$

$4(3)+4(-2i)+5i(3)+5i(-2i)$

$12-8i+15i-10i^2$

$12+7i-10(-1)$ $[\because i^2=-1]$

$12+7i+10$

$22+7i$

Therefore, the correct value of $(4+5i)(3-2i)$ is $22+7i$ .

4 0

3 years ago

Drag the expressions into the boxes to correctly complete the table. Polynomial Not a polynomial

uranmaximum [27]

The answer to the given question is as below:-

Polynomials:-

x³-7x²+9x-5x⁴-20

x⁵-5x⁴+4x³+2x-1

3x²-5x⁴+2x-12

Non-polynomial:-

x⁻5-5x⁻⁴+4x⁻³+2x⁻1-1

$\dfrac{4}{x^4}+ \dfrac{3}{x^3}-\dfrac{2}{x^4}-1$

$\sqrt[4]{x} -\sqrt[3]{x} 4+\sqrt{x}-8x+16$

<h3>What are polynomials?</h3>

A polynomial is a mathematical equation made up of indeterminates and coefficients and involves only addition, subtraction, multiplication, and non-negative integer exponentiation of variables. The exponents of the polynomials can not be irrational.

So the table will be formed as:-

Polynomials:- Non-polynomial:-

x³-7x²+9x-5x⁴-20 x⁻5-5x⁻⁴+4x⁻³+2x⁻1-1

x⁵-5x⁴+4x³+2x-1 $\dfrac{4}{x^4}+ \dfrac{3}{x^3}-\dfrac{2}{x^4}-1$

3x²-5x⁴+2x-12 $\sqrt[4]{x} -\sqrt[3]{x} 4+\sqrt{x}-8x+16$

Therefore the polynomials and non-polynomials are shown in the table above.

To know more about polynomials follow

brainly.com/question/2833285

#SPJ1

5 0

2 years ago

A ramp slopes from a warehouse door down to the street. The height of the ramp is 5 feet, and the ramp ends 10 feet from the bas

Tomtit [17]

If you graph this, your first point will be at (0,5), as the ramp is at the warehouse door but 5 feet up. The second point is (10,0) as it is touching the ground but it's 10 feet away from the warehouse.
To find slope, you do (y2-y1)/(x2-x1).
When substituting in the variables, you get (0-5)/(10-0), which is -5/10, which is simplified to -1/2. Of course, that is when the warehouse is Quadrant II. If you look at it from another point of view, the slope will be positive so your answer is A) 1/2.
If this was unclear feel free to comment :)

3 0

3 years ago

Read 2 more answers

Jason purchased a pack of game cards that was on sale for 13% off. The sales tax in his county is 8%. Let y represent the origin

Orlov [11]

The answer will be B. Hope it help!

5 0

3 years ago

wilhelmina has 8.3 ounces of peanut butter.if she makes 5 sandwijes with an equal amount ofbpeanut butter on each,how much peanu

kotykmax [81]

Peanut butter: 8.3 ounces

Sandwich: 5

Divide 8.3 by 5, for equal amount of peanut butter on each sandwich.

8.3/5 = 1.66

She puts 1.66 ounces of peanut butter on each sandwich.

3 0

3 years ago