d. every twentieth name on a roster of all students at school
Answer:
60
Step-by-step explanation:
Divide the number of questions answered correctly by his percentage
51 / 85 = 0.6
Now multiply that answer by 100 to see how many questions are on the quiz
0.6 x 100 = 60
Check your work by dividing that number by the number he answered correctly
51 / 60 = 0.85
If you distribute the 6(x-2) you would get 6x-12 so zero would equal zero
Answers:
u = 18
v = 20
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Work Shown:
The leg YZ is congruent to the left FH
This means YZ = FH and that leads to u+v-18 = 10u-8v
The hypotenuse ZX is congruent to the hypotenuse HG
This means ZX = HG and we get the equation 14v-14u+32 = v+u+22
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The system of equations we have so far is
u+v-18 = 10u-8v
14v-14u+32 = v+u+22
Let's get the equations into standard form
Start with the first equation
u+v-18 = 10u-8v
u+v = 10u-8v+18
u+v-10u+8v = 18
-9u+9v = 18
-9(u-v) = 18
u-v = 18/(-9)
u-v = -2
Note how we can solve for the variable u to get
u = v-2
which we'll use later
----------------------
Let's get the other equation into standard form as well
14v-14u+32 = v+u+22
14v-14u-v-u = 22-32
-15u+13v = -10
Now plug in u = v-2 and solve for v
-15u+13v = -10
-15(v-2) + 13v = -10
-15v+30+13v = -10
-2v+30 = -10
-2v = -10-30
-2v = -40
v = -40/(-2)
v = 20
Which means,
u = v-2
u = 20-2
u = 18
