4. Find CD and X . (3 points) x ^ 3 + 20 30 D x ^ 8 + 22x - 120 will mark brainliest

Mathematics

1 answer:

Aleonysh [2.5K]3 years ago

8 0

Answer:

CD = 15

x = 5

Step-by-step explanation:

Since BF ≅ FD and AE ≅ EC, then $EF = \frac{AB + CD}{2}$

So, $30 = \frac{x^{2} +20 + x^{2} + 22x - 120}{2}$

$60 = 2x^{2} + 22x - 100$

$2x^{2} + 22x - 160 = 0$

$2(x^{2} + 11x - 80) = 0$

2(x - 5)(x + 16) = 0

x = 5 or x = -16

If x = 5, then CD = $5^{2} +22(5) - 120 = 25 + 110 - 120 = 15$

Ix x = -16, then CD = will be a negative number which it cannot be.

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On three 150-point geography tests, you earned grades of 88%, 94%, and 90%. The ﬁnal test is worth 250 points. What percent do y

Semmy [17]

You must earn 243 points to have earned 93% of all possible points.

We first multiply each percentage on the previous tests by 150:

0.88*150 = 132
0.94*150 = 141
0.9*150 = 135

The total number of points possible is given by adding up the possible points for the three previous tests and the 250 for the last test:
150+150+150+250 = 700

93% of the 700 points would be 0.93(700) = 651 points.

Now we have 132+141+135+x (last test) = 651
408 + x = 651

Subtract 408 from both sides:
408+x-408 = 651-408
x = 243

7 0

2 years ago

Read 2 more answers

I need answers!!!!!!!!

aleksandrvk [35]

Answer:

a) 4.4583 b) Fiona

Step-by-step explanation:

First find the average of the numbers by adding them all together then dividing them by the amount of numbers given:

$(85 + 88 + 90 + 91 + 93 + 96 + 97 + 97 + 98 + 98 + 99 + 105)\div12= 1137\div12= 94.75$

Then find the difference between each number and the answer you got

$(85 - 94.75) + (88 - 94.75) + (90 - 94.75) + (91 - 94.75) + (93 - 94.75) + (96 - 94.75) + (97 - 94.75) + (97 - 94.75) + (98 - 94.75) + (98 - 94.75) + (99 - 94.75) + (105 - 94.75)\div12$