Answer:
x=72 and the exterior angle is 154
Step-by-step explanation:
We will call the unknown angle in the triangle y. Angle y and the angle (2x +10) form a straight line so they make 180 degrees.
y + 2x+10 =180
Solve for y by subtracting 2x+10 from each side.
y + 2x+10 - (2x+10) =180 - (2x+10)
y = 180-2x-10
y = 170-2x
The three angles of a triangle add to 180 degrees
x+ y+ 82 = 180
x+ (170-2x)+82 = 180
Combine like terms
-x +252=180
Subtract 252 from each side
-x+252-252 = 180-252
-x = -72
Multiply each side by -1
-1*-x = -72*-1
x=72
The exterior angle is 2x+10. Substitute x=72 into the equation.
2(72)+10
144+10
154
Answer:
t=9
Step-by-step explanation:
Move all terms that don't contain
t to the right side and solve.t=9
Answer:
This means that Alex answered 14 questions correctly
Step-by-step explanation:
<u>Step 1: Find an equation</u>
20 * 0.7 = x
<u>Step 2: Multiply</u>
20 * 0.7 = x
14 = x
Answer: This means that Alex answered 14 questions correctly
Let the three gp be a, ar and ar^2
a + ar + ar^2 = 21 => a(1 + r + r^2) = 21 . . . (1)
a^2 + a^2r^2 + a^2r^4 = 189 => a^2(1 + r^2 + r^4) = 189 . . . (2)
squaring (1) gives
a^2(1 + r + r^2)^2 = 441 . . . (3)
(3) ÷ (2) => (1 + r + r^2)^2 / (1 + r^2 + r^4) = 441/189 = 7/3
3(1 + r + r^2)^2 = 7(1 + r^2 + r^4)
3(r^4 + 2r^3 + 3r^2 + 2r + 1) = 7(1 + r^2 + r^4)
3r^4 + 6r^3 + 9r^2 + 6r + 3 = 7 + 7r^2 + 7r^4
4r^4 - 6r^3 - 2r^2 - 6r + 4 = 0
r = 1/2 or r = 2
From (1), a = 21/(1 + r + r^2)
When r = 2:
a = 21/(1 + 2 + 4) = 21/7 = 3
Therefore, the numbers are 3, 6 and 12.
