Question

alguém me ajuda por favor!!

Answer 1

d) y = 20; x = 3.

$\begin{cases} 4x+2y=52\\–4x+3y=48 \end{cases}$

0+5y = 100

$y = \frac{100}{5} \\ \boxed{\red{y = 20}}$

$4x + 2y = 52 \\ 4x + 2 \times 20 = 52 \\ 4x + 40 = 52 \\ 4x = 52 - 40 \\ 4x = 12 \\ x = \frac{12}{4} \\ \boxed{\red{x = 3}}$

e) b = 11 ; a = 9.

$\begin{cases} 2a–2b= –4\\–2a–3b =–51 \end{cases}$

0 –5b = –55

$b = \frac{ - 55}{5} \\ \boxed{\red{b = 11}}$

$2a - 2 \times 11 = - 4 \\ 2a - 22 = - 4 \\ 2a = - 4 + 22 \\ 2a = 18 \\ a = \frac{18}{2} \\ \boxed{\red{a = 9}}$

f) a = 5 ; b = 1

$\begin{cases}a+2b=7\\2a-2b=8\end{cases}$

3a +0 = 15

$3a = 15 \\ a = \frac{15}{3} \\ \boxed{\red{a = 5}}$

$a + 2b = 7 \\ 5 + 2b = 7 \\ 2b = 7 - 5 \\ b = \frac{2}{2} \\ \boxed{\red{b = 1}}$