Solve 2(5)^2+(a+1)(5)+(5+a)=84

$$2 ( 5 ) ^ { 2 } + ( a + 1 ) ( 5 ) + ( 5 + a ) = 84$$

Solve for a

$$a=4$$

Steps for Solving Linear Equation

Calculate 5 to the power of 2 and get 25.

$$2\times 25+\left(a+1\right)\times 5+5+a=84$$

Multiply 2 and 25 to get 50.

$$50+\left(a+1\right)\times 5+5+a=84$$

Use the distributive property to multiply a+1 by 5.

$$50+5a+5+5+a=84$$

Add 50 and 5 to get 55.

$$55+5a+5+a=84$$

Add 55 and 5 to get 60.

$$60+5a+a=84$$

Combine 5a and a to get 6a.

$$60+6a=84$$

Subtract 60 from both sides.

$$6a=84-60$$

Subtract 60 from 84 to get 24.

$$6a=24$$

Divide both sides by 6.

$$a=\frac{24}{6}$$

Divide 24 by 6 to get 4.

$$a=4$$