$a_n=a_1+d(n-1)\\\\a_8=a_1+d\cdot7\\\\a_{20}=a_1+d\cdot19\\\\a_{20}-a_8=a_1+19d-(a_1+7d)=12d\\\\56-20=2d\\\\12d=36\\\\d=3\\\\\\ a_1+3\cdot7=20\\\\a_1=20-21=-1$

6 0

3 years ago

HEYOO PEEPS Find the scale factor.

valentina_108 [34]

Answer:

I think it is 9

Step-by-step explanation:

as for number one I did 5×7=35 overall and 15×21= 315

then I did 315÷35=9 which is the scale factor.

hope this is correct and help u understand:)

7 0

3 years ago

Read 2 more answers

Determine whether the triangles are similar. If so, name the postulate or<br> theorem you used.

Mice21 [21]

Answer:

Yes, AA~

Step-by-step explanation:

because 2 of the angles are the same (90 and 52) they have to be the same. The triangle on the right is known to be 90 degrees because 52+38 is 90 and 180-90 is 90 and a triangle has to add up to 180 degrees

5 0

3 years ago

A health insurance payment of $34.55 was deducted from ms. Donaldson's earnings for the week. After the insurance deduction, pay

leonid [27]

I think that this quesion is missing some background, that is that Ms. Donaldson earned 907.10

So the 34.55 were deduced from this number, and the remaining amount was:

907.10-34.55=872.65

After this, further 28% were deduced, which means that 100-28=72% were left.

And this is:72%*872.55= 628.236 (which we round to 628.24!)

6 0

3 years ago