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4 years ago

Anyone know how to do this one? 2x+7y=-1 4x-3y=-19

1 answer:

7 0

2x+7y=-1 (1)
4x-3y=-19 (2)

multiply equation (1) by 2
4x + 14y = -2 (1')
4x - 3y = -19 (2)
---------------------subtract
17y = 17
y = 1

2x+7y=-1
2x+7(1)=-1
2x + 7 = -1
2x = -8
x = -4

answer
(-4, 1)

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If Steph Curry can shoot 72 free throws in 12 minutes, how many free throws

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3 years ago

Read 2 more answers

Taryn is shopping for a Christmas tree. At Home Depot the one she likes is $149.00 and she has a 15% off coupon. At Lowe's the o

Vitek1552 [10]

Answer:

Step-by-step explanation:

At home depot

Price of Christmas tree = $149.00

Discount = 15%

Amount discounted = 15% of $149

Amount discounted = 15/100 * $149

Amount discounted = 15 * 1.49

Amount discounted = $22.35

Amount she paid = $149-$22.35

Amount she paid = $126.65

At Lowe's:

Price of Christmas tree = $175.00

Discount = 260%

Amount discounted = 20% of $175

Amount discounted = 20/100 * $175

Amount discounted = 0.2 * 175

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3 years ago

A plane descends 1000 ft while flying 2.7 mi. What is the angle of descent?

Murrr4er [49]

Answer:

4.02°

Step-by-step explanation:

The angle of descent can be obtained using trigonometry ;

Since we have a right angled triangle ;

Let's use the relation:

Sin θ = opposite / hypotenus

Hypotenus = 2.7 miles

1 mile = 5280 feets

2.7 miles = (2.7 * 5280) = 14256 feets

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3 years ago

The area of the triangle formed by x− and y− intercepts of the parabola y=0.5(x−3)(x+k) is equal to 1.5 square units. Find all p

Juliette [100K]

Check the picture below.

based on the equation, if we set y = 0, we'd end up with 0 = 0.5(x-3)(x-k).

and that will give us two x-intercepts, at x = 3 and x = k.

since the triangle is made by the x-intercepts and y-intercepts, then the parabola most likely has another x-intercept on the negative side of the x-axis, as you see in the picture, so chances are "k" is a negative value.

now, notice the picture, those intercepts make a triangle with a base = 3 + k, and height = y, where "y" is on the negative side.

let's find the y-intercept by setting x = 0 now,

$\bf y=0.5(x-3)(x+k)\implies y=\cfrac{1}{2}(x-3)(x+k)\implies \stackrel{\textit{setting x = 0}}{y=\cfrac{1}{2}(0-3)(0+k)} \\\\\\ y=\cfrac{1}{2}(-3)(k)\implies \boxed{y=-\cfrac{3k}{2}} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{area of a triangle}}{A=\cfrac{1}{2}bh}~~ \begin{cases} b=3+k\\ h=y\\ \quad -\frac{3k}{2}\\ A=1.5\\ \qquad \frac{3}{2} \end{cases}\implies \cfrac{3}{2}=\cfrac{1}{2}(3+k)\left(-\cfrac{3k}{2} \right)$

$\bf \cfrac{3}{2}=\cfrac{3+k}{2}\left( -\cfrac{3k}{2} \right)\implies \stackrel{\textit{multiplying by }\stackrel{LCD}{2}}{3=\cfrac{(3+k)(-3k)}{2}}\implies 6=-9k-3k^2 \\\\\\ 6=-3(3k+k^2)\implies \cfrac{6}{-3}=3k+k^2\implies -2=3k+k^2 \\\\\\ 0=k^2+3k+2\implies 0=(k+2)(k+1)\implies k= \begin{cases} -2\\ -1 \end{cases}$

now, we can plug those values on A = (1/2)bh,

$\bf \stackrel{\textit{using k = -2}}{A=\cfrac{1}{2}(3+k)\left(-\cfrac{3k}{2} \right)}\implies A=\cfrac{1}{2}(3-2)\left(-\cfrac{3(-2)}{2} \right)\implies A=\cfrac{1}{2}(1)(3) \\\\\\ A=\cfrac{3}{2}\implies A=1.5 \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \stackrel{\textit{using k = -1}}{A=\cfrac{1}{2}(3+k)\left(-\cfrac{3k}{2} \right)}\implies A=\cfrac{1}{2}(3-1)\left(-\cfrac{3(-1)}{2} \right) \\\\\\ A=\cfrac{1}{2}(2)\left( \cfrac{3}{2} \right)\implies A=\cfrac{3}{2}\implies A=1.5$

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3 years ago