Answer:
The two triangles are congruent because the squares in the corner state it's 90 degrees, and the two tick marks show they are also congruent. \
Well, if you disregard the signs for a second, you can work this like a normal equation:
-6 - 12v = 90
-12v = 96
v = 8
Now just reincorporate the less than sign:
v < 8
<span>3x(5x^2 -7x +12) = 15x^3 - 21x^2 + 36x</span>