2x+8x=30. x= #of pens
10x=30. combine like terms
x=3. divide by 10 to isolate (get by itself) x
2(3)=6. the # of white pens are represented by 2x
6 white pens
hope this helped!
x² - 4x - 12 = 0
Factor the left side: (x + 2) · (x - 6) = 0
The equation is true if either factor is zero.
If (x + 2) = 0 then x = -2 .
If (x - 6) = 0 then x = 6 .
13. Pick a point and see which formula works.
Ay = -4, A'y = 7. Only the formula of selection D makes that translation.
14. Use the compound interest formula A = P*(1 +r/n)^(nt).
..1500*1.015^80 = 4935.99, matching selection C
15. The lid has a perimeter of 90", so the area of the sides is
.. 90" * 24" = 2160 in^2
The area of the lid is
.. 30" * 15" = 450 in^2
The gray area is (2160 -450) in^2 = 1710 in^2 larger, corresponding to selection C.
16. The only formula that maps (7, -1) to (21, -3) is that of selection D.
_____
The middle two problems are the only ones that require you to have prior knowledge. The others could be answered simply by seeing if the answers work.
The answer is 75! Explanation: Use the distance formula:)
