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3 years ago

Solve 3x+2y=7 and x-4y=-21 by using any method

Mathematics

1 answer:

kupik [55]3 years ago

8 0

Answer:

(- 1, 5 )

Step-by-step explanation:

Using the method of substitution.

Given the 2 equations

3x + 2y = 7 → (1)

x - 4y = - 21 → (2)

Rearrange (2) expressing x in terms of y by adding 4y to both sides.

x = 4y - 21 → (3)

Substitute x = 4y - 21 into (1)

3(4y - 21) + 2y = 7 ← distribute and simplify left side

12y - 63 + 2y = 7

14y - 63 = 7 ( add 63 to both sides )

14y = 70 ( divide both sides by 14 )

y = 5

Substitute y = 5 into (3)

x = (4 × 5) - 21 = 20 - 21 = - 1

Solution is (- 1, 5 )

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Larry has a gift card worth 400 for a local entertainment store Movies cost $20 each and newly released video games cost $50 eac

Vikki [24]

Answer:

All are correct.

Step-by-step explanation:

Let x be the number of movies and y be the number of newly released video games.

Larry has a gift card worth 400 for a local entertainment store Movies cost $20 each and newly released video games cost $50 each.

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$x+y\geq 9$

Check both inequalities of all given ordered pairs.

For (5,6),

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Point (5,6) satisfy both inequalities.

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$10+4\geq 9\Rightarrow 14\geq 9$

Point (10,4) satisfy both inequalities.

For (20,0),

$20(20)+50(0)\leq 400\Rightarrow 400\leq 400$

$20+0\geq 9\Rightarrow 20\geq 9$

Point (20,0) satisfy both inequalities.

For (15,2),

$20(15)+50(2)\leq 400\Rightarrow 400\leq 400$

$15+2\geq 9\Rightarrow 17\geq 9$

Point (15,2) satisfy both inequalities.

Therefore, all combination of movies and newly released video games Larry could purchase using his gift card.

4 0

2 years ago

20 points !!! -3/8x-20+2x>6

Semenov [28]

Answer:

$x > 16$

Step-by-step explanation:

$- \frac{3}{8} x -20+2x>6$

Add 20 to both sides:

$- \frac{3}{8} x + 2x > 26$

Multiply 8 on both sides:

$- 3x + 16x > 208$

$13x > 208$

Divide by 13 on both sides:

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3 years ago

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Alexxandr [17]

Answer:

5 must be added to both the terms to get the ratio 4:5.

Step-by-step explanation:

(3+x)/(5+x)=4/5

Therefore,

15+5x=20+4x

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I hope it's helpful!

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