Twelve is at least a number decreased by 7

12 ≥ x - 7

Step-by-step Explanation:

When it says twelve is at least, it means that twelve is at least equal to something and it can also be greater. And when it says a number decreased by seven, it means a number, which is the variable x because it’s unknown, minus 7. All of this can be expressed as 12 ≥ x - 7, which is true because a number, which is x, minus 7, is the smallest “thing” that 12 can equal to.

I hope you understand and that this helps with your question! :)

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.