The difference between double a number and 4 is 16

2x - 4 = 16

Step-by-step explanation:

'the difference' shows that its subtraction so u have to put a - in the equation

'double' means 2 and since you dont know the value of 'a number' you replace it with a variable like x. combine them and you get 2x

so far it should look like 2x -

4 is equal to 4 so just put a 4 in front of the subtraction sign

it'll look like 2x - 4 now

'is 16' basically means is equal to 16 so now ur equation should look like:

2x - 4 = 16

if you wanted to solve that u could add 4 to both sides then divide both sides by 2 and get x = 10

x = 10

Step-by-step explanation:

2x - 4 = 16

2x = 20

x = 10

Hope that helps!

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.