we know that
The sum of the internal angles of the triangle is equal to \(180\) degrees
in this problem we have
m∠2=\(2x\°\)
m∠3=\(5x\°\)
m∠1+m∠2+m∠3=\(180\°\)
Substitute the values and solve for m∠1
m∠1=\(180\°-(2x+5x)\°\)
m∠1=\(180\°-7x\°\)
Remember that
m∠1+m∠4=\(180\°\) -------> by supplementary angles
Substitute the value of m∠1 and find m∠4
m∠4=\(180\°-(180\°-7x\°)\)
m∠4=\(7x\°\)
therefore
the answer is
a) the measure of m∠1=\(180\°-7x\°\)
b) the measure of m∠4=\(7x\°\)
