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3 years ago

Evaluate the exponential expression: (2x)2nd power −3y2nd power =___, if x = 5 and y = 3.

Mathematics

1 answer:

damaskus [11]3 years ago

8 0

ANSWER

A. 73

EXPLANATION

The given expression is

$(2{x})^{2} - 3{y}^{2}$

We substitute x=5 and y=3 to obtain:

$(2 \times 5)^{2} - 3{(3)}^{2} = {10}^{2} - 3 \times 9$

This simplifies to,

$= 100 - 27$

$= 73$

The correct choice is A.

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It costs a total of R138.90 to purchase 10 loaves of bread and 12 litres of cooidrinks in a store. If the store raises the price

AlladinOne [14]

9514 1404 393

Answer:

R32.15

Step-by-step explanation:

Let x and y represent the original price of a loaf of bread and a liter of drink, respectively. The two relations given by the problem statement are ...

10x +12y = 138.90

10(1.2x) +12(1.1y) = 159.54

Multiplying the first equation by 1.2 and subtracting the second gives ...

1.2(10x +12y) -(10(1.2x) +12(1.1y)) = 1.2(138.90) -(159.54)

1.2y = 7.14 . . . . collect terms

y = 5.95 . . . . . divide by 1.2

The value of x can be found from the first equation.

10x + 12(5.95) = 138.90

10x = 67.50 . . . . . . . . . . . subtract 71.40

x = 6.75 . . . . divide by 10

Then the value of 3x+2y is ...

3(6.75) +2(5.95) = 32.15

The original price of 3 loaves and 2 liters is R31.15.

8 0

3 years ago

Which description best describes the solution to the following system of equations?

aleksandr82 [10.1K]

Answer:

Line y = –x + 4 intersects the line y = 3x + 3

Step-by-step explanation:

The solution is described as the point of intersection of the two lines. The description above is the only one that says anything about that.

___

<em>Comments on other answer choices</em>

Any line with finite non-zero slope intersects both the x- and y-axes. That fact does not describe the solution to a system of equations.

Any linear equation with an added (non-zero) constant will not intersect the origin. These two equations have +4 and +3 added, so neither line intersects the origin.

6 0

3 years ago

Last year at a certain high school, there were 50 boys on the honor roll and 100 girls

Sedbober [7]

there were 145 boys on the honor role and 60 girls equally given a total number of 205. This year, the number of boys decreased by 20% = 0.2*145=29

145-29=116

116 is this year number of boys on honor role

For girls.

=0.25*60=15

60-15=45

45 is this year number of girls on honor role.

Total number of students on honor role this year is 116+45 =161