What would be the first step in when solving the following linear system by substitution? x = 4 + y
x - 2y = 10

Linet passes through (4.5) and is perpendicular to the line shown on the condirate grid. what is the equation of line t in standard form?

If the speed of an electromagnetic wave is 100,000 cm/s and its wavelength is 100 cm, what is its frequency? a) 100,000 cycles per second (hz) b) 1 × 10-3 cycles per second (hz) c) 10,000,000 cycles per second (hz) d) 1,000 cycles per second (hz)

10% of 1,900,000. show me how you got the answer