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goldfiish [28.3K]
3 years ago
13

SOLVING SYSTEMS OF EQUATIONS BY SUBSTITUTION. 1. 2x+3y=1 -3x+y=15

Mathematics
1 answer:
ohaa [14]3 years ago
6 0
2x+3y=1 \\
-3x+y=15 \\ \\
\hbox{from the 2nd equation:} \\
-3x+y=15 \\
y=15+3x \\ \\
\hbox{substitute 15+3x for y in the 1st equation:} \\
2x+3(15+3x)=1 \\
2x+45+9x=1 \\
9x+2x=1-45 \\
11x=-44 \\
x=-4 \\ \\
\hbox{solve one of the equations for y}: \\
2x+3y=1 \\
2 \cdot (-4) + 3y=1 \\
-8+3y=1 \\
3y=1+8 \\
3y=9 \\
y=3 \\ \\
\hbox{the answer:} \\
x=-4 \\
y=3
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Can someone please help me with this problem.
iren [92.7K]
X^2 + 3x - 6

This is because x^2 and 3x have nothing they can combine with, leaving them as their own number. 1 + - 6 will give you -5 as adding to a negative only reduces not adds entirely.

Hope this helps!
8 0
3 years ago
Jenny drives from Paris to Rochefort, a distance of 483 km. her average speed on the journey is 84 km/h, she leaves at 9:50. Wha
Mrrafil [7]

The correct answer is 3: 35

Explanation:

To calculate at what time Jenny will arrive in Rochefort, the first step is to calculate the approximate time of the trip. Now, to calculate this consider the time of a movement (t) equals to the distance (d) divided by the speed (s), the process is shown below:

t = 483 km / 84 km/h

t = 5.75 hours

In this number 5 refers to the hours and 0.75 represents 45 minutes considering 0.75 x 60 minutes in one hour = 45 minutes. Therefore, the total time from Paris to Rochefort is 5 hours and 45 minutes. Now, to calculate the time of arrival add this result to the time of departure.

Add the hours: 5 hours + 9 hours: 14 hours

Add the minutes: 50 minutes + 45 minutes =95 minutes

95 minutes are equivalent to 1 hour (60) minutes and 35 minutes

Calculate the total

Hours: 14 hours + 1 hour = 15 hours or 3  in the 12 hour system (15 hours - 12 hours = 3 p.m.)

Minutes: 35 minutes

4 0
3 years ago
A test grade was 92%. 60 items were correct. How many test items were there?
Anna11 [10]
Set up an inequality:

\frac{92}{100}=\frac{60}{x}

Cross-multiply:
92x=6000
x=65 questions


6 0
3 years ago
Describe the rotational symmetry or symmetries of the figure.
kvv77 [185]

Answer:

A) 180º

Step-by-step explanation:

i wont be symmetric at 90º or 270º or 120º or 240º. and it has rotational symmetry

3 0
2 years ago
Solve.<br> 6n + 12 = -60 - 35
DedPeter [7]

Answer:

6n + 12 = -60 - 35

-12              -12

6n = -107

Divide by 6 on both sides:

N = -17.8333333333  around -17

Step-by-step explanation:

We need to isolate the variable meaning keeping the variable by itself on the left side. In order to do that we must get rid of any constants or co-efficients.

7 0
3 years ago
Read 2 more answers
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