X represent the number of laps Marcy swam, 114x represent the number of times Toni swam.

20 + 0.80(114x) + 15 + 0.85x = 257
20 + 91.2x + 15 + 0.85x = 257
92.05x + 35 = 257

Required equation is 92.05x + 35 = 257

3 0

3 years ago

Multiply.<br> (d+7)(d-7)<br> Simplify your answer.

romanna [79]

Answer:

$\huge\boxed{(d+7)(d-7)=d^2-49}$

Step-by-step explanation:

$\bold{METHOD\ 1:}\\\\(d+7)(d-7)\qquad|\text{use}\ (a+b)(a-b)=a^2-b^2\\\\=d^2-7^2=d^2-49\\\\\bold{METHOD\ 2:}\\\\(d+7)(d-7)\qquad|\text{use FOIL}\ (a+b)(c+d)=ac+ad+bc+bd\\\\=(d)(d)+(d)(-7)+(7)(d)+(7)(-7)\\\\=d^2-7d+7d-49\qquad|\text{combine like terms}\\\\=d^2+(-7d+7d)-49\\\\=d^2-49$

7 0

3 years ago

Pleas help me!!!

tigry1 [53]

The answer is about 900.

8 0

3 years ago