Find the values of t6 and d for the arithmetic sequence with t6= 4 and t10= -4

t1 = 14  d= -2

Step-by-step explanation:

tn = t1 + d ( n-1)

t6 = t1 + d(6-1)

4 = t1+ 5d

t10 = t1 +d (10-1)

-4 = t1 +d9

Take the two equations and subtract to eliminate a1

4 = t1+ 5d

- (-4 = t1 +d9)

4 = t1+ 5d

+4 =- t1 -d9

8  =   -4d

Divide each side by -4

8/-4 = -4d/-4

-2 =d

Now we can find t1

4 = t1+ 5d

4 = t1 + 5(-2)

4 = t1 -10

Add 10 to each side

4+10 = t1

14 = t1

A

Step-by-step explanation:

t1 = a

tn = a + (n-1)d

t6 = a + 5d = 4

a = 4 - 5d

t10 = a + 9d = -4

4 - 5d + 9d = -4

-8 = 4d

d = -2

a = 4 - 5(-2)

= 4 + 10

= 14

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.