-3(2a-3)+2=3(a+7) — step-by-step solution

Let's solve in

ℝ

- 3 \cdot (2 a - 3) + 2 = 3 \cdot (a + 7)

ⓘ Expand by multiplying each term inside the parentheses:

- 3 \cdot (2 a - 3)

- (6 a - 9)

3 \cdot (a + 7)

3 a + 21

- (6 a - 9) + 2 = 3 a + 21

ⓘ A minus sign before a parenthesis changes the sign of each of its terms:

- (6 a - 9)

- 6 a + 9

- 6 a + 9 + 2 = 3 a + 21

ⓘ Start from

9

and move forward

2

on the number line:

9 + 2

11

- 6 a + 11 = 3 a + 21

ⓘ We gather the terms in

a

on the right and the other terms on the left

11 - 21 = 3 a + 6 a

ⓘ Start from

11

and move back

21

on the number line, going below zero:

11 - 21

-10

■Like terms are grouped by adding their coefficients:

3 a + 6 a

9 a

-10 = 9 a

ⓘ Both sides are divided by

9

▶Solution obtained:

a = - \frac{10}{9}

The numeric value of:

a = - \frac{10}{9}

equals:

▷

a = \approx -1.1111