A sewing bag contains 3 gold buttons and 4 black buttons. How many buttons need to be added to the sewing bag so that there are 30% gold buttons?

3 black

Step-by-step explanation:

Currently: 7 buttons

30% gold so 70% should be black

70% = 0.7

(4+x)/(7+x) = 0.7

3+x = 0.7(7+x)

4+x = 4.9 + 0.7x

0.3x = 0.9

x = 3

step-by-step explanation:

∆abc has the points a(1, 7), b(-2, 2), and c(4, 2) as its vertices. formed with the point d(1, 2) as its third vertex, then ∆abd is triangle.