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kodGreya [7K]
3 years ago
5

Solve the simultaneous equations 3x + 2y = 30 3x - y = 21

Mathematics
1 answer:
Mrac [35]3 years ago
3 0

Answer:

x = 8 , y = 3

Step-by-step explanation:

3x + 2y = 30

3x - y = 21      -> y = 3x - 21

3x + 2 (3x - 21) = 30

3x + 6x - 42 = 30

3x + 6x = 30 + 42

9x = 72

x = 72/9 = 8

y = 3*8 - 21 = 24 - 21 = 3

∴ x = 8 & y = 3

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(6x - 3) - (-3x + 2)
nadezda [96]

Answer:

Step-by-step explanation:

Simplifying

6x + -3 = (3x + -2)

Reorder the terms:

-3 + 6x = (3x + -2)

Reorder the terms:

-3 + 6x = (-2 + 3x)

Remove parenthesis around (-2 + 3x)

-3 + 6x = -2 + 3x

Solving

-3 + 6x = -2 + 3x

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-3x' to each side of the equation.

-3 + 6x + -3x = -2 + 3x + -3x

Combine like terms: 6x + -3x = 3x

-3 + 3x = -2 + 3x + -3x

Combine like terms: 3x + -3x = 0

-3 + 3x = -2 + 0

-3 + 3x = -2

Add '3' to each side of the equation.

-3 + 3 + 3x = -2 + 3

Combine like terms: -3 + 3 = 0

0 + 3x = -2 + 3

3x = -2 + 3

Combine like terms: -2 + 3 = 1

3x = 1

Divide each side by '3'.

x = 0.3333333333

Simplifying

x = 0.3333333333

6 0
3 years ago
How do I know if it’s similar, congruent or neither?
Phantasy [73]

Answer:

These two triangles are congruent.

Step-by-step explanation:

You know this bc the markings on the drawing show that Angle B and Angle D are congruent. Also that AB is parallel to CD. This means that Angle BAC and Angle DCA are congruent by ALTERNATE INTERIOR ANGLES. Also, AC is congruent to itself. That makes the two triangles congruent by ANGLE-SIDE-ANGLE.

Now, you need to know that "congruent" triangles (and shapes in general) are the same size and shape. "Similar" triangles (shapes) are the same shape but not necessarily the same size.

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