Hi. Can you explain test 6, section 4, number 14. Thanks.

Sure. The table tells you that the sunflower’s height was 36.36 cm on day 14 and 131.00 cm on day 35. The equation that models that interval well should give you about 36 cm when you substitute 14 for t and give you about 131 cm when you substitue 35 for t. Therefore, you can try each choice using those numbers until you find the one that works.

A) h = 2.1(14) – 15 = 14.4 <– Nope, too small!

B) h = 4.5(14) – 27 = 36 <– Looks good, better check the other value.
h = 4.5(35) – 27 = 130.5 <– Oh yeah, that’s pretty darn close. That’s gotta be our answer.

The other way to go here is to calculate the slope between the two points you know:


The only answer choice with a slope of 4.5 is B, so again, that must be the answer!

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