Answer:

Step-by-step explanation:
The figure given has two similar triangles: ΔABC and ΔDEF. Although the triangles are similar, their orientation is different and ΔDEF is flipped. Since the triangles are similar, their side lengths are proportional to each other. Given the orientation of the triangles, we can still see that the diagonal (hypotenuse) for the larger triangle is AC and the smaller is DF. The only answer that matches these up proportionally is the third one. Looking at the second side, BC, we can see that this matches up to the longer leg of EF on the smaller triangle. Final answer being:

Rational 3667/1000
^^^^^^^^^^^
Subtract 8d from both sides
21 = 12d + 5 - 8d
Simplify 12d + 5 - 8d to 4d + 5
21 = 4d + 5
Subtract 5 from both sides
21 - 5 = 4d
Simplify 21 - 5 to 16
16 = 4d
Divide both side by 4
16/4 = d
Simplify 16/4 to 4
4 = d
Switch sides
d = 4
<u>Check answer</u>
8d + 21 =12d + 5
Let d = 4
8 × 4 + 21 = 12 × 4 + 5
Simplify 8 × 4 to 32
32 + 21 = 12 × 4 + 5
Simplify 12 × 4 to 48
32 + 21 = 48 + 5
Simplify 32 + 21 to 53
53 = 48 + 5
Simplify 48 + 5 to 53
53 = 53
Answer:
log1/8
Step-by-step explanation: