Prove Propositions 32 and 33 of the Maasei Hoshev: a) 1 + (1 + 2) + (1 + 2 + 3) + ... + (1 + 2 + ... + n) =    1 2 + 32 + ... + n 2 , if n is odd; 2 2 + 42 + ... + n 2 , if n is even.

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation:

72 is the answer to this problem

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18

umumumumum

im not sure