Substiution method: y + 9 = 1/5x and

Mathematics

1 answer:

uranmaximum [27]3 years ago

4 0

Y+9=1/5x menjadi y= 1/5x -9
sesudah ini sibtusika n dalam persamaan 4x - 5y = -15x
 4x -5(1/5x-9)= -15 x
4x + x+45=-15x
5x +45 = -15x 45=-20x
x=-45/20
x= -9/4

y+9 =1/5x
y = 1/5(-9/4)-9
y = -189/20
(-9/4,-189/20)

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Brianna is going to a carnival that has games and rides. Each game costs $1.25 and each ride costs $3.75. Brianna spent $18.75 a

maxonik [38]

Answer:

6 games and 3 rides

Step-by-step explanation:

Let the number of games Brianna played be x,

and the number of rides she went on be y.

Total cost for games= 1.25x

Total cost for rides= 3.75y

Since number of games is twice the number of rides,

x= 2y -----(1)

Total costs= cost of games +cost of rides

$18.75= 1.25x +3.75y$

Multiply the whole equation by 4 to remove the decimals:

$75= 5x +15y$

Simplify by dividing the whole equation by 5:

$15 = x + 3y$

Label the equation:

x +3y= 15 -----(2)

Although we can solve these 2 equations by substitution, since the question requires us to graphically solve, we have to graph 2 linear lines.

I will choose 3 points to plot on the graph for each equation:

x= 2y -----(1)

$\begin{tabular}{|c|c|c|c|} \cline{1-4}x & 2(1) = 2&2(2) = 4&2(3) = 6\\ \cline{1-4}y & 1 &2&3\\ \cline{1-4}\end{tabular}$

x +3y= 15 -----(2)

x= -3y +15

$\begin{tabular}{|c|c|c|c|} \cline{1-4}x & -3(1)+15= 12& -3(2)+15= 9& -3(3)+15= 6\\ \cline{1-4}y & 1 &2&3\\ \cline{1-4}\end{tabular}$

Let's plot these points on a graph paper. Then, join them with a straight line for each straight line graph. Please see the attached picture for the graph.

From (1): y= ½x

From (2): 3y= 15 -x

y= 5 -⅓x

From the graph, the solution of the equation is (6,3). The solution is the point on the graph in which the 2 lines intersect.

x- coordinate: 6

y- coordinate: 3

Thus, Brianna played 6 games and went on 3 rides.