So you question is most likely about a triangle DEF with the 3 angles being named D, E, F. The triangle would look something like the image attached below.
If that is what is being asked then i need more info to answer but
By Definition it would be 180 degrees.
No. x cannot equal 2 and 7
First, let's re-arrange to slope-intercept form.
x + 8y = 27
Subtract 'x' to both sides:
8y = -x + 27
Divide 8 to both sides:
y = -1/8x + 3.375
So the slope of this line is -1/8, to find the slope that is perpendicular to this, we multiply it by -1 and flip it. -1/8 * -1 = 1/8, flipping it will give us 8/1 or 8.
So the slope of the perpendicular line will be 8.
Now we can plug this into point-slope form along with the point given.
y - y1 = m(x - x1)
y - 5 = 8(x + 5)
y - 5 = 8x + 40
y = 8x + 45
If alonzo is x then the equation is
x + (x +3) + 2(x + 3) = 57
Which equals
x + x + 3 + 2x + 6 = 57
4x + 9 = 57
4x = 48
x = 12
This means alonzo is 12 years old and alexis is 3 years older so alexis is 15 years old
Answer = 15 years old