Practise the method.Example 1For y=5×2x, find the y−intercept as ay−value.yy = 5 × 2^x. Horizontal axis: x; vertical axis: y. Horizontal range -3 to 3; vertical range 0 to 40.-202010203040xy=5×2xShow worked answerAnswer: 5At the y−axis x=0, and 20=1, so y=5.Example 2For y=20(0.8)x, what happens when x increases by 1?Show worked answerAnswer: The value decreases by 20%Each unit step multiplies the previous value by 0.8, retaining 80% and losing 20%.Example 3An exponential model is y=2×2x. What is y when x=2?Show worked answerAnswer: 8Substitute x=2:y=2×4=8.