You need to find the value of a so solve the first equation in terms of z:

5a + z = 7
z = 7 - 5a

then substitute the result (7 - 5a) into the second equation:

-4a - 1(7 - 5a) = -5
-4a + (-1 x 7) + (-1 x -5a) = -5
-4a - 7 + 5a = -5
-4a + 5a = -5 + 7
a = 2
a = \( \frac{2}{1} \)
a = 2

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 67° - 44° = 69°

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 4 x 5
a = 20