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Anit [1.1K]
3 years ago
6

Use substitution to solve the system of equations.

Mathematics
2 answers:
polet [3.4K]3 years ago
8 0
The answer is (3,-6)
murzikaleks [220]3 years ago
4 0
X-3*(-2x)=21
x+6x=21
7x=21
X=21/7
X=3
Now you substitute x=3 in the other equation
Y=-2*3
Y=-6
You might be interested in
What value makes 3(a+1.5)= -1.5 true
Reika [66]
First, write the equation:
3(a+1.5) = -1.5
Next, you can distribute 3 into the parentheses by multiplying 3 by a and 1.5. It should look like this:
3a + 4.5 = -1.5
When trying to find the value of a variable, you want to get the variable to one side of the equation by itself. Subtract 4.5 from both sides of the equation to get:
3a = -6
Now, divide both sides by 3 to get your final answer:
a= -2
The value that makes the equation true is -2
Hope this helped!
3 0
3 years ago
I need help with linear functions can anybody help me?
NNADVOKAT [17]

I can help you! Just let me how what the questions are

7 0
3 years ago
If tan a = 3/4 find the value of sin 3a
Effectus [21]
T=-1

sinA=sin(π/2-3A), A=2nπ+π/2-3A, 4A=2nπ+π/2, A=nπ/2+π/8 where n is an integer.

Also, π-A=2nπ+π/2-3A, 2A=2nπ-π/2, A=nπ-π/4.

The hard way:

cos3A=cos(2A+A)=cos(2A)cosA-sin(2A)sinA.

Let s=sinA and c=cosA, then s²+c²=1.

cos3A=(2c²-1)c-2c(1-c²)=c(4c²-3).

s=c(4c²-3) is the original equation.

Let t=tanA=s/c, then c²=1/(1+t²).

t=4c²-3=4/(1+t²)-3=(4-3-3t²)/(1+t²)=(1-3t²)/(1+t²).

So t+t³=1-3t², t³+3t²+t-1=0=(t+1)(t²+2t-1).

So t=-1 is a solution.

t²+2t-1=0 is a solution, t²+2t+1-1-1=0=(t+1)²-2, so t=-1+√2 and t=-1-√2 are solutions.

Therefore tanA=-1, -1+√2, -1-√2 are the three solutions from which:

A=-π/4, π/8, -3π/8 radians and these values +2πn where n is an integer.

Replacing π by 180° converts the solutions to degrees.

3 0
3 years ago
Add.<br><br> −2.35+(−1.602)<br><br> Enter your answer in the box.
Lerok [7]

Answer:

-3.952

Step-by-step explanation:

just remember when adding two negatives, the result will be negative

5 0
3 years ago
Find the values of x when y =1
Ivahew [28]
Graph the rationale functions f(x)x2+3X-1/x+1 by identifying its key features.
8 0
3 years ago
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