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weeeeeb [17]
3 years ago
9

-x+7y=5,-4x+y=-7 System of equations substitution

Mathematics
1 answer:
Leno4ka [110]3 years ago
5 0

Answer:

<h2>x = 2, y = 1 → (2, 1)</h2>

Step-by-step explanation:

\left\{\begin{array}{ccc}-x+7y=5\\-4x+y=-7&\text{add}\ 4x\ \text{to both sides}\end{array}\right\\\\\left\{\begin{array}{ccc}-x+7y=5&(1)\\y=4x-7&(2)\end{array}\right\qquad\text{subtritute (2) to (1)}\\\\-x+7(4x-7)=5\qquad\text{use the distributive property}\\\\-x+(7)(4x)+(7)(-7)=5\\\\-x+28x-49=5\qquad\text{add 49 to both sides}\\\\-x+28x=5+49\qquad\text{combine like terms}\\\\27x=54\qquad\text{divide both sides by 27}\\\\\boxed{x=2}

\text{Put the value of}\ x\ \text{to (2):}\\\\y=4(2)-7\\\\y=8-7\\\\\boxed{y=1}

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Which mark on the tape measure is closest to 2.23607 inches?
Lapatulllka [165]

Answer:

  5.7 cm or 2 1/4 in

Step-by-step explanation:

Your tape measure is not shown.

  On my tape measure, 5.7 cm is the closest mark. On the inch scale, 2 1/4 inches is the next-closest mark.

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On a tape measure graduated in 1/32 inch between 2 and 3 inches, you can find the closest mark by rounding to the nearest 32nd:

  2.23607 × 32 ≈ 71.55 ≈ 72 --- 32nds of an inch

  72/32 = 2 1/4 . . . . the closest mark on an inch ruler graduated in 32nds

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For a ruler graduated in millimeters, you can find the closest millimeter in the same way. There are 25.4 mm to the inch.

  2.23607 in × 25.4 mm/in ≈ 56.80 mm ≈ 57 mm

  57 mm = 5.7 cm . . . closest mark on metric scale

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When we check the error, we find the metric mark is closer than the inch mark.

  5.7 cm ≈ 2.24409 in . . . . error of 0.00802 in

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5 0
3 years ago
Use formula A=LW to find the length of a rectangle when the width is 35 ft and the area is 1,750 sq ft
Ludmilka [50]

Answer:

the length of the rectangle is 50 ft

Step-by-step explanation:

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6 0
2 years ago
What does B equal if the problem is y=5/-9x+B
NikAS [45]

Answer:

y=5/-8x+b

or y-b =5/-8x

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6 0
3 years ago
Drag each equation to show if it could be a correct first step to solving the equation 8(x + 5) = 56.
lana66690 [7]

8(x + 5) = 56

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5 0
3 years ago
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Choose the correct simplification of the expression (−2x + 8y)(9x − 3y).
Romashka-Z-Leto [24]
For these kinds of expressions use FOIL (first, outside, inside, last).

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Now combine them all:

-18x^2 + 78xy - 24y^2
6 0
3 years ago
Read 2 more answers
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