Solve for x: 39 - 7x = -4 (7x + 7) = 4

Subtract 39 from both sides

-7x = -4 - 39

Simplify -4 - 39 to -43

-7x = -43

Divide both sides by -7

x = -43/-7

Two negative make a positive

x = 43/7

For the second equation;

Simplify brackets

7x + 7 = 4

Subtract 7 from both sides

7x = 4 - 7

Simplify 4 - 7 to -3

7x = -3

Divide both sides by 7

x = -3/7

Simplifying

39 + -7x = -4(7x + 7) + 4

Reorder terms

39 + -7x = -4(7 + 7x) + 4

39 + -7x = (7 * -4 + 7x * -4) + 4

39 + -7x = (-28 + -28x) + 4

Reorder the terms

39 + -7x = -28 + 4 + -28x

Combine like terms -28 + 4 = -24

39 + -7x = -24 + -28x

Solving

39 + -7x = -24 + -28x

Solve for variable x                                                                                            all terms x left, all others right.

Add '28x' to each side of the equation.

39 + -7x + 28x = -24 + -28x + 28x

Combine like terms -7x + 28x = 21x

39 + 21x = -24 + -28x + 28x

Combine like terms -28x + 28x = 0

39 + 21x = -24 + 0

39 + 21x = -24

Add '-39' to each side of the equation.

39 + -39 + 21x = -24 + -39

Combine like terms: 39 + -39 = 0

0 + 21x = -24 + -39

21x = -24 + -39

Combine like terms -24 + -39 = -63

21x = -63

Divide each side by 21

x = -3

Simplifying

x = -3

cosine

step-by-step explanation: