We do like the following:
Set the first number is a and the second is b.
We have two equations: a+2xb=24, 2xa+b=21
And we have 2xa+4xb=48 or 2xa=48-4xb
So: 48-4xb+b=21 or -3xb=21-48=-27 and we got b=-27:(-3)=9 and a= 6
a=6 and b=9
Answer:
it is an acute scalene triangle
The algebraic expression for a phrase is: 
.
Hope this help.
Since a complementary angle is two angles that equal 90 degrees the compliment of angle B would be 30 degrees since 60+30 = 90.
