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the work of a student to solve a set of equations is shown: equation a: y = 16 – 2z equation b: 7y = 2 – 4z

step 1: –7(y) = –7(16 – 2z) [equation a is multiplied by –7.]
7y = 2 – 4z [equation b]
step 2: –7y = 16 – 2z [equation a in step 1 is simplified.]
7y = 2 – 4z [equation b]
step 3: 0 = 18 – 6z [equations in step 2 are added.]
step 4: 6z = 18
step 5: z = 3

in which step did the student first make an error?

step 3
step 4
step 1
step 2

step 2

Step-by-step explanation:

The student first made an error in the step 2.

Because if we simplify the equation A in step 1, we should distribute the right side of the equation following the rule a(b-c) = a*b +a*(-c)

So, it would be

–7y = (-7)*(16)+(-7)*(-2z)

=> -7y = -112 + 14z

3; 9 is 8 to -4

step-by-step explanation:

hope it you

step-by-step explanation:

sin(7pi/6 - pi/3)  

= sin(7pi/6 - 2pi/6)  

= sin(5pi/6)  

= sin(pi - pi/6)  

= sin(pi/6)  

= 1/2  

sin 7pi/6 - sin pi/3  

= sin (pi + pi/6) - sin pi/3  

= -sin pi/6 - sin pi/3  

= -1/2 - sqrt(3)/2  

= -(1+sqrt(3))2