Write an equivalent expression for 3x + 21

Mathematics

1 answer:

Arada [10]3 years ago

7 0

3(x + 7)
hope this helps

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.y = 2x - 3; x = - 4<br>how do you do this?<br>

Svetach [21]

y = 2(-4) - 3

y = -8 - 3

y = -11

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4 years ago

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Karolina [17]

Answer:

Step-by-step explanation:

the second one , why? because 7a-12a=-5a

4 - 8 = -4

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3 years ago

7x-2y=16 11x+6y=32.3<br>how to solve this math problem

Aneli [31]

Answer:

Step-by-step explanation:

These types of equations are called simultaneous equations and the method we can use to solve these type of equations is either Substitution, Elimination and Graphing.

We use substitution here because it is easier.

Equation 1

$7x-2y=16$

Equation 2

$11x+6y=32.3$

Lets take equation 1

$7x-2y=16\\7x=16+2y\\x=\frac{16+2y}{7}$

This is our equation 3 , now put it inside equation 2.

$11x+6y=32.3\\11(\frac{16+2y}{7} )+6y=32.3\\\frac{176+22y}{7} +6y=32.3\\\frac{176+22y+42y}{7}=32.3\\176+22y+42y=226.1 \\\\42y+22y=226.1-176\\64y=50.1\\y=\frac{50.1}{64} \\y=0.783\\$

We found the value of y , now to find the value of x insert the value of y in equation 3

$x=\frac{16+2y}{7}\\x=\frac{16+2(0.783)}{7} \\x=\frac{16+1.566}{7}\\x=\frac{17.566}{7}\\x=2.509$

Solved ! See the attached image on both the straight line graphs i have attached for better understanding. Where both the lines intersect each other is our value of (x , y) respectively.