Solve {0a+40(70-a)=2500

$$\{ 0 a + 40 ( 70 - a ) = 2500$$

Solve for a

$$a = \frac{15}{2} = 7\frac{1}{2} = 7.5$$

Steps for Solving Linear Equation

Anything times zero gives zero.

$$0+40\left(70-a\right)=2500$$

Use the distributive property to multiply 40 by 70-a.

$$0+2800-40a=2500$$

Add 0 and 2800 to get 2800.

$$2800-40a=2500$$

Subtract 2800 from both sides.

$$-40a=2500-2800$$

Subtract 2800 from 2500 to get -300.

$$-40a=-300$$

Divide both sides by -40.

$$a=\frac{-300}{-40}$$

Reduce the fraction \frac{-300}{-40} to lowest terms by extracting and canceling out -20.

$$a=\frac{15}{2}$$