Find the value of x.

x = 19

Step-by-step explanation:

The sum of both angles will be equal to a supplementary angle. A supplementary angle is when two angles add up to be 180°. Write an equation and solve for x.

3x + 5 + 7x - 15 = 180

~Combine like terms

10x - 10 = 180

~Add 10 to both sides

10x = 190

~Divide 10 to both sides

x = 19

Best of Luck!

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!

the answer is a.

135 and 80

step-by-step explanation: