3(x-21)=10x — step-by-step solution

Let's solve in

ℝ

3 \cdot (x - 21) = 10 x

ⓘ Expand by multiplying each term inside the parentheses:

3 \cdot (x - 21)

3 x - 63

3 x - 63 = 10 x

ⓘ We gather the terms in

x

on the right and the other terms on the left

-63 = 10 x - 3 x

ⓘ Like terms are grouped by adding their coefficients:

10 x - 3 x

7 x

-63 = 7 x

ⓘ Both sides are divided by

7

x = - \frac{63}{7}

ⓘ We simplify the fraction by dividing the numerator and the denominator by

7

, their greatest common divisor:

- \frac{63}{7}

-9

▶Solution obtained:

x = -9