20x+5y=120
10x+7.5y=80 multiply this one by 2
___________

20x+5y=120
20x+15y=160 subtract

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-10y=-40 divide both sides by -10
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y=4

20x+5(4)=120 plug 4 in for y in the first equation
20x+20=120 multiply
20x=100 subtract
x=5 divide to find x

5 0

3 years ago

What decimal represents 6/24? 0.6 0.416– 0.25 0.1 PLEASE HELP MEEEEE

lana66690 [7]

0.25 is the answer I think

6 0

3 years ago

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50 POINTS BRAINLIEST MATH

MrRa [10]

Answer:

$B=\frac{2A}{h}-b$

Step-by-step explanation:

To solve this B needs to be isolated. First we must multiply both sides of the equation by 2 to get rid of the fraction on the left side. Next, divide both sides by h to get rid of the h on the left side. Finally, subtract b form both sides to get B by itself.

6 0

3 years ago

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Given points (r1, u1 ) and (r2, u2) in polar coordinates, obtain a general formula for the distance between them. Simplify it as

sertanlavr [38]

Answer:

$d=\sqrt{r_1^2+r_2^2-2r_1r_2\cos(u_2-u_1)}$

Step-by-step explanation:

The Law of Cosines gives an immediate result. No translation to Cartesian coordinates is necessary. That law makes use of the angle between the vectors, u2-u1

$d^2=r_1^2+r_2^2-2r_1r_2\cos(u_2-u_1)\\\\\boxed{d=\sqrt{r_1^2+r_2^2-2r_1r_2\cos(u_2-u_1)}}$

6 0

3 years ago