Solve 21 - 3(a - 7) = 2a + 20 | Equatix - Math Solver

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Example

3(r+2s)=2t-4

a⋅(b-2)=3b

3(r+2s)=2t-4

a⋅(b-2)=3b

Question

$$21-3(a-7)=2a+20$$

Solve for a

$a = \frac{22}{5} = 4\frac{2}{5} = 4.4$

Steps for Solving Linear Equation

Use the distributive property to multiply $-3$ by $a-7$.

$$21-3a+21=2a+20$$

Add $21$ and $21$ to get $42$.

$$42-3a=2a+20$$

Subtract $2a$ from both sides.

$$42-3a-2a=20$$

Combine $-3a$ and $-2a$ to get $-5a$.

$$42-5a=20$$

Subtract $42$ from both sides.

$$-5a=20-42$$

Subtract $42$ from $20$ to get $-22$.

$$-5a=-22$$

Divide both sides by $-5$.

$$a=\frac{-22}{-5}$$

Fraction $\frac{-22}{-5}$ can be simplified to $\frac{22}{5}$ by removing the negative sign from both the numerator and the denominator.

$$a=\frac{22}{5}$$