Solve S_{7}=35-35(0.4)^7/1-0.4

$$S _ { 7 } = \frac { 35 - 35 ( 0.4 ) ^ { 7 } } { 1 - 0.4 }$$

Solve for S_7

$$S_{7}=58.23776$$

Steps for Solving Linear Equation

Calculate 0.4 to the power of 7 and get 0.0016384.

$$S_{7}=\frac{35-35\times 0.0016384}{1-0.4}$$

Multiply 35 and 0.0016384 to get 0.057344.

$$S_{7}=\frac{35-0.057344}{1-0.4}$$

Subtract 0.057344 from 35 to get 34.942656.

$$S_{7}=\frac{34.942656}{1-0.4}$$

Subtract 0.4 from 1 to get 0.6.

$$S_{7}=\frac{34.942656}{0.6}$$

Expand \frac{34.942656}{0.6} by multiplying both numerator and the denominator by 1000000.

$$S_{7}=\frac{34942656}{600000}$$

Reduce the fraction \frac{34942656}{600000} to lowest terms by extracting and canceling out 192.

$$S_{7}=\frac{181993}{3125}$$

Assign S_7

$$S_{7}≔58.23776$$