Answer:
(a) Expanded form:

(b) The value of the expression: -21
Step-by-step explanation:
Given

Solving (a): The expanded form:
This means that we substitute the values of i from 1 to 4 in the above expression.
So, the expression becomes:

Solving (b): The value of the expression
To do this, we simply substitute the given values of X1, X2....... in the expression.
This gives:
So, the expression becomes:

Simplify each bracket



<em>Hence, the result of the expression is -21</em>
Triangles are congruent
Step-by-step explanation:
Law of Side, Side, Angle
Thier base are same (PR).
Thier 1 side is equal to 2 inch (PS = RQ).
Thier 1 angle is equal (/_ PRQ = /_ RPS)
So, Its prove that both triangles are congruent.
<span><span><span><span>2a</span>−9</span>+<span>2a</span></span>=<span><span><span>−<span>2a</span></span>+15</span>+<span>2a</span></span></span><span><span><span>4a</span>−9</span>=<span>15
</span></span>Step 2: Add 9 to both sides.<span><span><span><span>4a</span>−9</span>+9</span>=<span>15+9</span></span><span><span>4a</span>=<span>24
</span></span>Divide both sides by 4.<span><span><span><span><span>4a/</span>4</span></span></span>=<span><span>24/<span>4
</span></span></span></span>Answer:<span>a=<span>6</span></span>
A full circle is 360 degrees. A half circle is 180. And a quarter is 90. If he turns 47 degrees then he only needs to turn 223 degrees more till he faces north.