Answer:
see below
Step-by-step explanation:
cos(420°) = cos 60 = 1/2
sin(450°) = sin 90 = 1
l=51
m=78
n=51
n and l have the same value since it’s an isosceles triangle, so that’s why I doubled 4x-9
X=0 is definitely the answer but I belive how u solve it is 7×X=0 and that leaves -4 because it would be 0-4 so u just take out the zero. I think, but the answer is 0.